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No one wants a bulky cooling vest weighing them down. That's why UnderCool cooling vest weighs less than 2lbs including the cooling packs.


Made from breathable mesh and wicking fabrics, UnderCool cooling vest is designed to keep you cool and dry.


Our slim design conforms to your shape, making it possible to wear UnderCool cooling vest under your clothes. You can stay cool and no one else has to know.


You've never cooled like this before...
See why UnderCool is the world's #1 invisible cooling vest.


Easy as 1, 2, 3...

 Photo of cooling packs.


Before going out, refreeze your cooling packs 20min in ice water, 40 min freezer or 60 in in the fridge.

 Photo of cooling packs being inserted into the UnderCool cooling vest.


Slide your frozen cooling packs into the hidden pockets on the back of your UnderCool cooling vest.

 Photo of woman doing yoga while wearing UnderCool cooling vest.


Wear your UnderCool cooling vest and experience cooling relief like never before.


How to Wear

 Photo of woman wearing an UnderCool under her shirt. The cooling vest is virtually undectable.

Sick of bulky cooling vests cramping your style? We get it.

Just because you want to be cool and comfortable doesn't mean you have to sacrifice your appearance. That's why we designed UnderCool, the first cooling vest to be worn under your clothes. You can wear virtually anything over the UnderCool and no one will be able to tell you're wearing a cooling vest.

UnderCool cooling vest features adjustable straps and velcro on the front to effortlessly fit a wide variety of shapes and sizes. Four cooling pockets along the back provide cooling relief where you need it the most.

Remember, stay cool, play cool, be cool!


UnderCool Sizing Guide

Size Waist
Extra Small 24" - 28" 61 cm - 71 cm
Small 28" - 32" 71 cm - 81 cm
Medium 34" - 38" 86 cm - 97 cm
Large 40" - 46" 102 cm - 116 cm
Extra Large 48" - 52" 121 cm - 132 cm

Waist Measurement: If you bend to the side, you will crease in the middle of your body; this is your natural waist. That's where you want to take your waist measurement.

*Womens Sizing Guide:  Please note sizing is dependent on waist size not bust size.

*Sizing Guide: ThermApparel recommends ordering a size smaller than your usual T-shirt size. (If wear a large T-shirt, a Medium UnderCool will fit best.)


New shipping options.

We ship to USA, Canada, Mexico, New Zealand, UK, Ireland, Denmark, The Netherlands, Germany, India, Egypt, and Israel.

Live in Australia?

UnderCool Cooling Vest now available at RehaCare in Australia. A distributor of rehabilitation products with a primary focus on therapy. RehaCare offer customers innovative and new product solutions that improve the independence and quality of life for individuals with injuries and disabilities.

Live in a different part of the world?

We aren't just design explorers, we like exploring the world too! Help us help you get an UnderCool wherever you need it.

Questions about our vests or shipping? Reach out to the ThermApparel team toll-free at 855-232-7233, write to us through our website’s contact form or chat with us via live chat. We always respond because, otherwise, that wouldn't be cool.