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Getting Started

  • You don’t have to take the packs out to charge them. Put the whole vest with packs included into the freezer or fridge for 45 to 60 minutes (or ice water for 20 minutes) until they are fully solid again.
  • If you took the packs out of the vest, slide the frozen cooling packs into each of the pockets in the back of your UnderCool.
  • Your UnderCool is now charged and ready to be worn.

How to Wear

  • Unfasten the Velcro.
  • Place your arms through each arm hole.
  • Fasten the Velcro on your front, tight enough so the cooling packs rest firmly on your back.
  • Wear whatever you like over your UnderCool.

Cooling and Recharging

  • Undercool will cool as long as the packs haven't phased to complete liquid - this may occur in 1-2 hours depending on your level of activity and the ambient temperature.
  • To recharge the packs, put them back in the freezer or fridge for 45 to 60 minutes (or ice water for 20) until they are fully solid again.
  • Enjoy a day safe from the heat!

Washing and Care

  • Remove all cooling packs from the vest. (They will be destroyed if you keep them in there!)
  • Close the velcro front and place in a small net laundry bag.
  • Wash UnderCool in cold water with like colors.
  • Dry and store flat.


Consult your health care professional prior to using this or any body cooling product for a medical condition. UnderCool cooling packs are designed for the specific objective of cooling the body. ThermApparel will not be liable for injuries or damages resulting from 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.