How to get the right UnderCool for you.


UnderCool Sizing Guide

Size Natural Waist
Extra Extra Small - XXS  20" - 24"

51 cm - 61 cm

Extra Small  24" - 28"

 61 cm - 71 cm


 28" - 32"

71 cm - 81 cm

 34" - 38"

 86 cm - 97 cm

 40" - 46"

 102 cm - 116 cm
Extra Large - XL

 48" - 52"

 121 cm - 132 cm
Extra Extra Large - XXL 55" - 60"

140 cm - 152 cm

Waist Measurement:

Currently UnderCool comes in 7 sizes XXS - XXL to fit a wide variety of body shapes and sizes, because "one size fits all" really isn't true. UnderCool needs to fit your body like a glove to give you the best cooling support.

UnderCool sizing is based on your natural waist size, not your pant size. Not sure where your natural waist is or how to get the correct sizing? 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. Then check our handy sizing guide and order the correct UnderCool for you.

Women's Sizing Guide:

Please note sizing is dependent on natural waist size, not bust, hip or pant size.
Depending on your bust size you will wear a vest that is 1-2 sizes smaller than your t-shirt size. 

Men's Sizing Guide:

Please note sizing is dependent on natural waist size, not chest or pant size. 
If you were to wear a skin tight t-shirt under a dress shirt, what size would the skin tight t-shirt be? Go with that size.

Don’t Have a Fabric Measuring Tape?

You can measure your waist the same way with a straight ruler and:
String / Yarn
Dental Floss
Charging cord from your phone

Need Help With Sizing? Fill Out the Form, Get a Free FitKit.

The ThermApparel Fit Kit is loaded with tips and suggestions and a handy measuring tape so you will get the correct size when you order. Fill out the form below and we will send you a FitKit!

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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.