Stay Warm. All Day.

The UnderWarmer is a compression fitted body warmer. Eight large air-activated heat packs are built-in, staying warm for up to 12 hours.

The UnderWarmer Heated Body Warmer Packaging

Enjoy your winter activities like never before!

The UnderWarmer heated body warmer shirt is convenient, super comfortable and best of all- it works really well! UnderWarmer was specifically designed to be affordable and convenient for the everyday guy or gal spending a long day in the cold.

Unlike hand warmers and foot warmers, which only help extremities that have already gotten cold, the UnderWarmer PREVENTS your CORE from getting cold which causes cold extremities. How? Because a cold body core is the cause of icy extremities. Best of all, unlike all those bulky layers you’ve tried, the UnderWarmer is extremly lightweight and won’t slow you down.

Whether you are tailgating all day, hunting, fishing, or going for a long motorcycle ride you CAN stay warm for the entire day, even in negative digits. For just a few bucks, you have a portable, wearable radiator, ready to go when you are. Just grab your UnderWarmer!

Air Activated And Ready in 30 Minutes- Air activated heat packs mean that you’re ready for the cold at a moment’s notice. It’s the best way to stay warm with zero prep – no charging needed. Simply open the package, pull on the shirt, and feel the warmth (up to100°F/38°C) heating up your core.

ReSeal and ReUse- The UnderWarmer is essentially a single-use body warmer.  However, If only worn for a few hours, place it in an air tight bag and it will stop producing heat, essentially going dormant. When you remove the UnderWarmer it will reactivate.  This can be done a few times, for up to 12 total hours of heat!

Feel Snug And Gently Stimulated– The UnderWarmer is a soft, lightweight compression shirt. So it feels really, really good. But most importantly, that snug fit means the warmth stays right where you need it – near your skin. (Make sure to use our detailed size chart and diagram to choose the best size to fit your upper body so you get the ultimate UnderWarmer experience.)

Perfect For Cold Weather Activities– You always thought that you had to choose between your favorite winter activity and staying warm. But no longer. Whether you’re deer hunting, ice fishing, hiking or camping in the cold outdoors, the UnderWarmer heated body warmer shirt will make it a wonderfully warm experience.

Great Gift For Football Fans – Gift your tailgating spouses and buddies (or yourself!) with a way to enjoy cold weather football games AND stay warm.