You've never cooled like this before...


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.

Photo of woman doing yoga while wearing UnderCool cooling vest.


Put on your UnderCool 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 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 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.