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, the UnderCool cooling vest is designed to keep you cool and dry. Our flexibility is unmatched!



Our slim design conforms to your shape, you can even wear the 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, store your cooling packs in a cold place for about one hour.

 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.


Put on 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 the UnderCool 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!


UnderCool Sizing Guide

Size Waist Length
Extra Small 24" - 28" 61 cm - 71 cm 15" 38 cm
Small 26" - 30" 66 cm - 76 cm 16" 41 cm
Medium 28" - 32" 71 cm - 81 cm 17" 43 cm
Large 32" - 38" 81 cm - 96 cm 19" 48 cm
Extra Large 40" - 45" 101 cm - 114 cm 19" 48 cm

Quick Reference Sizing Guide:

ThermApparel recommends ordering a size smaller than your ususal t-shirt size. (If you wear a large t-shirt, a medium UnderCool will fit best.)


New shipping options!

We ship to the US, Canada, Mexico, Australia, New Zealand, and the UK!

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.