Best Thermal Underwear Reviewed and Rated

In a Hurry? Editors choice:
Minus33 Expedition Bottom
Test Winner: Minus33 Expedition Bottom
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Thermal underwear or thermals may come as an afterthought to most people. However, its usefulness is apparent when you take to the road, go hiking, or camping in the dead cold of November. Selecting the right pair of thermals can be challenging with such a wide variety of unfamiliar options.

There are design features, variations in size, weight, color, and the coverage that these products offer. Each variety can have its advantages and usefulness to a particular purpose. Like lightweight options support a high level of cardio and aerobic activity due to their conduciveness to moderate temperatures.

This article features a list of some of the best products that the current market has to offer. Here, you will find all the information you might need to make a worthwhile purchase. Keep reading to answer any question you may have about thermal underwear.

Standout Picks

Carhartt Base Force
Carhartt base force leggings promise to raise your spirits and lust for adventure even in the most depressing of cold days. These leggings offer a protective base layer capable of insulting every part south of the waist. The Carhartt base layer also synchronizes well with whatever pants you layer over them.
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Minus33 Expedition Bottom
The minus33 merino base layer bottoms are one of the best classic mid-weight technical leggings the market has to offer. This weight profile makes the leggings ideal for use in all types of winter sports. Unlike most base layer clothing, these leggings are comfortable and fit snugly without restricting your movement.
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Nike Pro Tights
The next product on the list comes from the number one sporting band in the world. The Nike pro tights are a popular winter sporting option that goes well with all amateur, pro, and extreme winter sports. These insulating bottoms also come equipped with quick-drying fabric to ensure you stay as dry and warm as possible.
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Duofold Varitherm
The Duofold mid-weight thermal leggings provide essential protection from extreme colds yet allow for unrestricted movement. This factor makes them ideal for a wide range of winter sports and outdoor survival. As the name suggests, these leggings provide a dual-layer design that keeps you warm.
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Fruit of the Loom
The fruit of the loom waffle thermal underwear pants is ideally suited for lovers of the classic design. These classic bottoms are the most widely available product on the list. This wide availability means you can get deals on the product across all online vending platforms and even outlet stores.
Amazon Link
Ekouer Base Layering Set
The Ekouer is a 2-piecer thermal underwear suit that offers full-body protection for those cold winter months. Both the bottoms and the top have a 95% polyester and 5% elastane material. The interior of this suit is lined with soft thermal fleece that keeps you warm and comfortable through the day.
Amazon Link
Under Armour Cold Gear
Under Armour, cold gear authentic is ideal if you like to break some serious sweat in the winter. The dual-layer fabric and brushed interior of these pants keep you toasty warm and comfortable. While the smooth and fast-drying exterior of the leggings keeps you drier even with extended use.
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Rocky Long Johns
Rocky thermals are a set that comes with long leggings and a matching long-sleeved top for complete protection from the elements. This 2-piecer option will keep you warm and comfortable thought any season of the year. The low weight profile of this suit makes it ideally suitable for a range of physical activates.
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Thermajane Long Johns Set
Thermajane is another example of a breathable 2-piecer base layer set. This set comes in neutral like black, pink, purple, white, and olive, which compliment any shade of skin. Thanks to a 92% polyester and 8% spandex material, this set is stretchy, comfortable, warm, and moisture-wicking.
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TSLA Blank
The TSLA blank women’s top and bottom set is an affordable yet premium quality alternative. This set consists of a fleece-lined long-sleeved top and matching leggings. This suit is comfortable, fitting, and insulation is enhanced with the innovative heatfit design.
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Criteria Used for Evaluation

Materials

Fabrics constitute the outfit.

The type of material used in the manufacture of any clothing speaks volumes to its comfort, quality, and durability. There are many natural, synthetic, and hybrid fibers used in the global textile industry. Since no material is made equal, here are some of the materials commonly used in creating base layer clothing.

Synthetic fibers like polyester and their blends typically dry very fast which suits them for base layer clothing. This aspect makes apparel made from these materials ideal for cold, wet, as well as hot conditions. Traditionally synthetics had an odor accumulation problem. Luckily, advancements have brought enhanced synthetics that deal with such issues.

Cotton is incredibly absorbent and driers slowly, so stay away from base layer options made of 100% cotton. Avoid the fabric because you will still sweat under your clothing; however, cotton blended fabrics can still work. Synthetic fibers and bamboo merge with cotton to produce performance fabrics that have softness, enhanced moisture-wicking as well as stretchiness locked in.

Silk is an incredibly smooth fabric, which makes it suitable for users with, particularly sensitive skin. This fabric can be treated with chemicals to enhance the clothing’s moister wicking properties. The only major drawback is that it required meticulous care and it traps odor.

Merino wool has nearly replaced traditional wool in textile production thanks to its softness. This fiber is blended with stretchy fabrics like spandex to make warm yet stretchy clothing. Clothing made from merino wool comes highly recommended because of the moisture-wicking capabilities supple feel.

Polyester blends like spandex, Lycra, and nylon feature in almost every textile product made in the world. Base layer clothing that utilizes such fibers in their construction are stretchy and nearly feel like a second skin. Outfits featuring such materials also have a fleece lining to prevent the garment from locking odor while enhancing the warmth they offer.

Bamboo is a relatively new fabric to the market. This fabric is mixed with other fibers like cotton and polyester for a stronger material. Bamboo is effective at wicking moisture and retains its shape allowing manufactures to create clothing that offers more compression.

Use

When shopping for thermal underwear; first, envision your needs.

Outdoor explorers like hikers, campers, and climbers need to stay dry and warm as well as add some odor resistance to their clothing. Base layer clothing provides those qualities as well as resistance to dirt and grime thanks to enhanced fabrics. Naturally, soft and warm fabrics like cotton and wool are combined with synthetic fibers to make clothing that is both functional and comfortable.

Snow sports like snowshoeing and skiing require long treks through harsh snow-covered landscapes, which exposes you to freezing temperatures. Light to heavyweight base layering clothing affords the wearer some protection from these harsh elements. These clothes effectively prevent heat from escaping while wicking away at sweat to ensure you stay dry and warm.

Upper torso activities like mountain climbing and kayaking lead to a heavy accumulation of lactic acid, which causes cramps and swelling. Base layer options made with thick fabric, to a loose fit on the chest area can reduce oxygen debt and the accumulation of lactic acid in the muscles. Such clothing offers some compression as well as the circulation of warm oxygen-rich blood in the muscle tissues.

Backpackers need clothing that is comfortable, and warm enough to sleep in because of the on-the-go nature of their journeys. Both synthetic and natural fabrics work well in the preferred base layer clothing. The base layer clothing should also wick at moisture and be easy to doff even while on the move.

Casual hikers require warm, moisture-wicking, and warm base layer clothing to provide them with insulation and protection from the elements. Their base layer clothing options also need to be light and have anti-chafing features like welded seams. Both synthetic and natural fibers can provide these qualities.

Commuter cyclists face constant battles with oncoming traffic as well as chilly winds and the constant threat of rain. Light merino base-layer clothing with waterproof shells are ideally suited to the needs of such commuters. Such materials provide the necessary protection, and the user need not worry about getting hot and sweaty under such layers of clothing.

All-weather motorcyclists hit very high speeds that expose them to frosty wind chills. Heavy synthetic-based base layer clothing further enhanced with a windproof membrane is ideal for the needs of such users. Such clothing enhances the insulating effects of your helmet, jacket, balaclava, etc.

Insulation

The first consideration should be if the thermals keep you warm.

Aspects such as the materials used, weight, and general design of thermals can tell you the most about the insulation such a product offers. Thermals need to trap heat while allowing for ventilation and wicking away at sweat and moisture. This “trapping” and retention of body heat keeps your body from going numb from the cold.

Proper Insulation can also protect you from hyperthermia, frostbite, cold, and flu infections. This protection is as a result of your body, retaining a temperature that prevents such infections and reactions. However, relying solely on thermal underwear is a foolhardy choice; please also invest in additional gear like high quality gloves, socks, balaclavas, and anything else that will keep you warm.

As mentioned earlier materials play a huge role in the insulating qualities of any item of clothing. Merino wool is a natural fiber that keeps you warm even when you sit or stand in the cold for some time. Wool is soft and fluffy, which makes it comfortable to wear, and the fluffy fibers act as small pockets that trap hence insulate hot air.

Thermals made with such materials also reduce the ratio at which heat is lost to the environment. This type of clothing fits snuggly close to the skin. Therefore, very little of this hot air gets lost during the transfer back to the body.

The trick to proper insulation is creating a secondary layer of hot air between your thermals and skin. Air does not conduct heat or remain heated as effectively as water does. Therefore, you also need to control sweat, wind, and the amount of moisture that comes from the environment. Most of the products on this list have these aspects under control; however, your choice remains subjective to your personal needs.

Weight

The materials used and the activity for which the thermals are to be used can be a determining factor.

If you are shopping for something for regular or daily usage, then a thin and lightweight option is the best bet. Such thermals easily slip into your jeans and other clothing without bunching up. As for the cold winter months, you are safer if you bet on a heavier option to shield you from the cold.

Each weight option has its advantages and drawbacks. Your needs and range of activities serve as the best way to determine the weight of your clothing. Here are the main categories you will run into while shopping for thermals.

Ultra-lightweight thermals are good for mildly cold climatic conditions. You can layer them under sports gear for additional warm for early morning outdoor activities when the season is not too cold. You can also sleep in them or use them as casual daily wear.

Lightweight thermals have a bit heavier than ultra-light but less bulky than heavyweight models. Such thermals are ideal for daily use as well as a variety of winter outdoor sports and activities. You can use them for skiing or running, jogging or hiking during the winter.

Some lightweight options offer some compression that ensures you have warm blood flowing through your muscles. The key to using such clothing outdoors is to move around a lot to sustain this blood flow. Therefore, as long as you keep moving these thermals will keep the cold at bay.

Mid-weight thermals are suited for use in regions where users are exposed to passing bouts of harsh temperatures. They offer slightly less insulation when compared to heavyweight models but provide more flexibility and freedom of movement. These qualities make them appropriate for use in activities such as sledding, snowshoeing, skiing, and extreme winter sports.

Heavyweight thermals are ideal for extreme levels of cold. Their sheer weight makes them great for spending time in such environments, even without constant motion. If you are interested in backpacking through the winter, camping or hiking then you should go for such clothing.

Style

Thermal underpants come in various cuts, heights, and sizes.

The first thing you to consider when looking at the style of base layer clothing is the amount of coverage you need. Aside from the coverage, you can also look at how much compression you need from your clothing. The ease of use can also determine your preference for a particular style over another one.

Long shirts
Some models come in the shape of long sleeve shirts that usually have a crew neck or an extendible turtleneck. These shirts provide your upper body and arm with protection from the elements. The most beneficial aspect of long-sleeved shirts is you can easily roll up the sleeves or take them off when it gets too hot.

Leggings
Base layer pants look like tights because of their form-fitting and compression design. They cover everything south of the waistline. Aside from insulating your body from the elements, these tights can also be used by cyclists and runners that have issues with chaffing.

Boxer/briefs
These provide the same level of coverage, regular boxers, and briefs offer. These thermal underpants are suitable for places with subzero temperatures. When layering clothing for such regions, you will need as many layers as possible.

Two-piece suits
This base layer clothing comes with both a long sleeve top and legging bottoms. Such an outfit gives the advantage of being able to take part of it off when it gets hot. Some of the products on this list that feature this design also work well as sleepwear or casual gear.

Union suits
All thought union suits are outdated and not commonly used these days they still warrant a token mention. These suits look more like jumpsuits or onesie jammies. The amount of coverage and stiffness of such suits makes them inappropriate for a range of activities, but they make great pajamas for the winter months.

Best Thermals for Men and Women

1. Carhartt Base Force

Where to buy
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Carhartt Base Force
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Carhartt base force leggings promise to raise your spirits and lust for adventure even in the most depressing of cold days. These leggings offer a protective base layer capable of insulting every part south of the waist. The Carhartt base layer also synchronizes well with whatever pants you layer over them.

These base layer leggings are made from 100% cotton soft to keep you comfortable and warm. This product also features ring knitting to prevent the leggings from ripping and features stain break technology that keeps them for longer. This model is fully machine washable and features a tagless design that prevents irritation.

The 9.8-ounce weight profile gives the leggings additional resistance to the cold. Color options for this model are black and neutral colors. An added advantage to these leggings is the compression that they offer: it’s tight but not constricting. This level of compression allows for unrestrictive movement and flexibility.

The waist features a snug fit, comfortable, and elastic waistband. This feature prevents the pants from sagging too low or ridding too high on your waistline. You can spend a bit more for the matching Carhartt base force super cold weather crew neck for full-body protection.

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2. Minus33 Expedition Bottom

Where to buy
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Minus33 Expedition Bottom
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The minus33 merino base layer bottoms are one of the best classic mid-weight technical leggings the market has to offer. This weight profile makes the leggings ideal for use in all types of winter sports. Unlike most base layer clothing, these leggings are comfortable and fit snugly without restricting your movement.

The Katmai expedition merino33 base layer bottoms have a 400g weight and feature a 100% merino wool material, similar to the near perfect Smartwool Merino 250 bottoms. Merino wool has natural sweat-wicking and insulating properties that allow manufacturers to make lightweight yet practical clothing. These bottoms will protect you from extreme colds and the harmful effects of sun rays thanks to a 50+ UPF factor.

The Katmai expedition bottoms feature flat seaming that reduces friction to counter chafing and other irritations. The cuffs on this model are ribbed to prevent the bottoms from bunching up and for you to pull the leggings over the top layer easily. These base layer bottoms are fit to compression for proper blood circulation, which keeps you warmer in the outdoors.

These bottoms come in a wide range of styles, cuts, and lengths for both men and women. With such a wide selection, one can quickly get a custom form-fitting pair of base layer leggings. The Katmai expedition merino33 base layer bottoms have a mass following and come highly recommended for hunting, hiking skiing and other winter activities.

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3. Nike Pro Tights

Where to buy
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Nike Pro Tights
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The next product on the list comes from the number one sporting band in the world. The Nike pro tights are a popular winter sporting option that goes well with all amateur, pro, and extreme winter sports. These insulating bottoms also come equipped with quick-drying fabric to ensure you stay as dry and warm as possible.

These leggings feature a choice blend of polyester 90% and spandex 10% that protects you while ensuring a flexible range of movement. These features are enhanced with compression fitting and Nike Dri-fit technology, similar to their capable Dri-fit Transform. The interior of the leggings also has a mesh construction on the highly heated zones to improve ventilation and prevent chafing.

The leggings compression helps in contain and highlighting key muscle groups to prevent strain and injury. The ankle-length design of these base layer pants makes them ideal for layering under clothing. The supple and stretchy consistency of the fabric reduces chafe-inducing friction.

This model comes in neutral shades of black, white, and grey, which don’t shout for attention. The only drawbacks to this product are an unravelling waistband and the lack of a fly in the design. The Nike pro tights offer the same reliability one expects from any product featuring the tick logo.

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4. Duofold Varitherm

Where to buy
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Duofold Varitherm
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The Duofold mid-weight thermal leggings provide essential protection from extreme colds yet allow for unrestricted movement. This factor makes them ideal for a wide range of winter sports and outdoor survival. As the name suggests, these leggings provide a dual-layer design that keeps you warm.

The material blend featured on these leggings is a 60% cotton and 40% polyester mix. This design works by trapping warm air around the covered area, and the cuffs featured on the leggings prevent the intrusion of cold air. This dual-ply cotton/polyester material construction also wicks sweat and has Flatlock seaming to counter chafing.

The Duofold leggings have a convenient fly for added ease when answering the call of nature. This model comes with black, ultramarine, Poseidon blue, and winter white as the only color options. The machine-washable nature and drawstring featured on these leggings add to your convenience.

The mid-weight 11-0unce profile of these leggings is not as suffocating as some other models the market has to offer. This secondary skin base layer ensures that you are comfortable and not as encumbered when wearing them. You can layer these leggings under any of your favorite jeans, khakis, or chinos on any outdoor activity.

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5. Fruit of the Loom

Where to buy
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Fruit of the Loom
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The fruit of the loom waffle thermal underwear pants is ideally suited for lovers of the classic design. These classic bottoms are the most widely available product on the list. This wide availability means you can get deals on the product across all online vending platforms and even outlet stores.

Mass production usually breeds a slump in quality, but you don’t have to worry about that should you choose the fruit of the loom. These leggings are made from a polyester 65% and cotton 35% material mixture. This fabric mix ensures that the pants provide a moderate level of insulation and enhanced moisture-wicking and redistribution.

The waffle design featured in the leggings enhances the heat retention capabilities of the leggings, and the comfort offered. Elastic spandex ankle cuffs and waistband ensure a snug fit and prevent the leggings from sagging or ridding too high. The fruit of the loom leggings also come with tag-free instructions printed on the back of the bottoms.

These leggings are machine washable and can be dried with moderate temperature settings. Aside from coming at a bargain price, these leggings are just as durable as any other on this list is. You can never go wrong with a niche brand that has stood the test of time like the fruit of the loom.

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6. Ekouer Base Layering Set

Where to buy
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Ekouer Base Layering Set
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The Ekouer is a 2-piecer thermal underwear suit that offers full-body protection for those cold winter months. Both the bottoms and the top have a 95% polyester and 5% elastane material. The interior of this suit is lined with soft thermal fleece that keeps you warm and comfortable through the day.

Despite this fleece, lining the suit is still breathable enough to prevent you from overheating while engaged in intense winter activities. This long sleeve mid-weight option comes without those annoying manufacturer tags. The whole suit has a contemporary fitting design, and the leggings have a comfortable and functional elastic waistband.

The Ekouer has a snug fit that is not too tight or loose. The high quality material used in the construction of this suit is soft, which reduces friction and irritation. This suit comes in many colors, sizes, and options for both men and women.

The Ekouer suit is comfortable and warm enough to be worn to bed like pajamas on unusually cold days. The mid-weight profile of this suit makes it ideally suited for layering with other clothes. There are no worries of the material bunching up or sticking out of upper layers of clothing.

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7. Under Armour Cold Gear

Where to buy
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Under Armour Cold Gear
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Under Armour, cold gear authentic is ideal if you like to break some serious sweat in the winter. The dual-layer fabric and brushed interior of these pants keep you toasty warm and comfortable. While the smooth and fast-drying exterior of the leggings keeps you drier even with extended use.

As opposed to products from other lines that feature the same design cues, the cold gear authentic does not cling to the skin when exposed to moisture. The trademarked fabric blend featured on this model has antimicrobial properties that counter malodor. These features culminate into a pair of leggings that will not interfere with your workout routine or pace.

These leggings also feature a level of compression that facilitates sufficient blood flow and faster recovery time. The seams on the cold gear authentic are flat and welded to counter chafing. The overall design caps off at the smooth elastic waistband to give you a definitively streamlined shape.

The only drawbacks that come with these leggings are their sensitivity to washing: best to hand wash to preserve the leggings’ integrity. The fleece lining is also worth noting, especially if you need some leggings for the snow. Under Armour cold gear authentic come at a high price point but this is justifiable since they are among the best performance fleece leggings you can find in the market.

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8. Rocky Long Johns

Where to buy
Amazon Link
Rocky Long Johns
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Rocky thermals are a set that comes with long leggings and a matching long-sleeved top for complete protection from the elements. This 2-piecer option will keep you warm and comfortable thought any season of the year. The low weight profile of this suit makes it ideally suitable for a range of physical activates.

This suit is made from an ultra-soft polyester/spandex fabric blend. This fabric mix is enhanced further by a thermal knit pattern that prevents shrinkage for a longer-lasting product. An elastic waistband keeps the leggings in place, and double-layered cuffs prevent the warmth from escaping.

The interior of both the top and bottoms features a soft fleece lining while the outer shell is has a smooth finish. This design means you can layer other activewear or regular clothing over the suit for additional protection from the cold. This suit comes in a variety of colors that can match anything you wear over them.

This suit fits snuggly without constricting your body or revealing your shape. This fitting, coupled with the opaque finishing of the fabric makes this suit also ideal for use as casual wear. The sleeves and legs of the rocky also don’t bunch under layered clothing.

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9. Thermajane Long Johns Set

Where to buy
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Thermajane Long Johns Set
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Thermajane is another example of a breathable 2-piecer base layer set. This set comes in neutral like black, pink, purple, white, and olive, which compliment any shade of skin. Thanks to a 92% polyester and 8% spandex material, this set is stretchy, comfortable, warm, and moisture-wicking.

The construction features a four-way stretch design, which gives the wearer an unlimited range of motion. This range of motion makes this set ideal for skiing, snowshoeing, and running or even for indoor use. The long sleeve top offers optimal coverage, and it is breathable and odor resistant.

Another twist to old technology is the use of Argan oil in the process of weaving the fabric. The purpose of this oil preserves the suppleness of the material even with repeated washing. The Thermajane suit comes at a reasonable price and delivers the same quality that a premium thermal suit provides.

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10. TSLA Blank

Where to buy
Amazon Link
TSLA Blank
Amazon Link

The TSLA blank women’s top and bottom set is an affordable yet premium quality alternative. This set consists of a fleece-lined long-sleeved top and matching leggings. This suit is comfortable, fitting, and insulation is enhanced with the innovative heatfit design.

The heatfit design minimizes on the material waist to ensure you have mobility and the suit wicks at moisture effectively. The mobility factor of the suit is enhanced further by a four-way stretch fabric construction.

The microfibers used in the construction of the suit have antimicrobial properties that keep malodor away by eliminating the bacteria that cause it. Additionally, these microfibers are enriched through crewneck stretch technology to prevent shrinkage. However, for good measure, wash the suit in cold water to preserve its integrity.

Sizes run from small to 2X-large with a handy sizing chart to help you settle on the right one for you. The TSLA blank women’s top and bottom set works great when layered under other clothing for all types of outdoor activities. You can also use the suit indoors, and it makes excellent alternative sleepwear in those cold winter months.

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