Starting at $199.99

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Free Shipping on orders over $90

UnderCool features:
  • Lightweight (SlimCool weighs 1.3 lbs / ExtendedCool weighs 1.9 lbs)
  • Concealable under clothing
  • 1-3 hours of cooling depending on cooling pack type
  • 60 day money back guarantee
Garment Facts:
  • 4-way stretch, adjustable straps and velcro front for best fit and comfort
  • Wicking fabrics to keep you dry
  • 88% Nylon/12% spandex
  • Machine washable, lie flat to dry
Cooling Pack Facts:
  • ThermApparel PCM freezes at 70F (21C) so its safe for contact with the skin
  • Works great in dry and humid conditions
  • ThermApparel bio-based PCM is non-toxic and biodegradable
  • Fast recharge times (30 min icewater, 45 min freezer, 60 min fridge)
This package includes:
  • 1 UnderCool garment with choice of color, black or white
  • 3,4, or 6 cooling packs based on sizing. SlimCool or ExtendedCool.
  • Free shipping option at checkout!


Please review our sizing chart below to ensure the best fit for your UnderCool:

 Size  Natural Waist (in)  Natural Waist (cm)
 XXS  18" - 24"  46cm - 61cm
 S  24" - 31"  61cm - 78cm
 M  31" - 40"  78cm - 101cm
 L  40" - 51"  101cm - 129cm
 XXL  51" - 64"  129cm - 162cm

Sizing Tips:

  • Sizing is based on your natural waist, not your hips, pants, chest or cup size.
  • Measure against your skin
  • Take your measurements in front of a mirror to make sure it is level.
  • UnderCool should fit your body like a glove to give you the best cooling.

Cooling Pack Care and Storage Recommendations:
  • When not in use, store Cooling Packs in the solid state, this means the fridge, freezer, or a room less than 70F/21C
  • Cooling packs left in their melted state for extended periods of time may reduce the lifespan of the cooling packs.
  • When handled properly packs should last 2-3 years and can be refrozen thousands of times.
  • To wash your cooling packs, use warm soapy water in the sink.  Do not put them in the washer, dryer, or dishwasher.
  • Please review our Return and Exchange Policy, Warranty Policy and User Guide.
Consult your doctor or health care professional prior to using this or any cooling products for a medical condition.  ThermApparel LLC will not be liable for injuries or damages resulting from the misuse or misapplication of our products.


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.