The UnderWarmer® is a single-use, compression fitted base-layer shirt. 8 HEAT PACKS are built-in and will activate within minutes of removing from its packaging. When ready to use, simply remove The UnderWarmer® from its packaging. Upon opening, heat activation begins and will take approximately 30 minutes to reach its maximum temperature of over 100f/38c.
FIND YOUR SIZE BELOW
UNISEX SIZING (inches):
Youth sizes 60-100 lbs
Small Chest: 30 – 34 inches
Medium Chest: 35- 39 inches
Large Chest: 40 – 44 inches
X-Large Chest: 45 – 49 inches
Todd **Amazon Review** –
Perfect for hunting in sub-zero weather. This fit right and tight, kept me warm throughout the majority of the day, and the weather was in the negative digits. The only thing is I wish they made pants to legs warm. Great product!
henderson_4 **Amazon Review** –
This was amazing. Bought and wore it for an outdoor flag football tournament I was in. Kept me warm while it was in the low 40’s and flexible and didn’t restrict movement. Stayed warm longer than the 10 hrs. Will definitely buy again at some point.
B whtstone **Amazon Review** –
WORKS GREAT!! Absolutely GREAT to keep warm in hunting season!!!
kim d. **Amazon Review** –
It really works. This was amazing. Went to football game 20 degree and snow. It really worked well never got cold once. I was impressed so worth the money.
Maria **Amazon Review** –
Went to a game at Lambeau Field when it was 8 degrees outside. This vest was a lifesaver! Made a huge difference when I put it on. It fit perfect for me. I wore an under armor cold gear shirt underneath as well as one over the vest, and a medium vest fit perfect.
Frank **Amazon Review** –
Great for sports events! I wear these between an undershirt and my jacket and they really help keep me warm during sporting events. I’m 5’11” 190 and an X-large fits perfect.
calbow **Amazon Review** –
This under warmer is amazing. It does fit tight like a compression shirt and you can rip it if you are rough with it as I tore it taking it off. I am 5’7” and 200 lbs and XL fits like a glove. It is very light material and stretches as it is a one use product. You can reuse it if you put it in an air tight package but I use mine all day. It really does a good job of keeping you warm in cold weather. I put it on over my long underwear and was toasty warm in 28 degree weather with a 15 mph wind. You can wear it as an undershirt but I would only do that if it gets colder than 0 degrees. I bought 6 more and will buy more when I get down to my last two. Fast shipping. Awesome product I met two guys that designed this product at a sports show a couple years ago and they are great guys. Like to see local guys do good. I highly recommend the under warmer
Great product! Exceeded expectations.
These under warmers are fantastic. Awesome product, fast shipping great price. I have used them in a tree stand 25 degrees with a 15 mph wind kept me very warm.
A **Amazon Review** –
This is one of the best purchases I have made this year. I bought 3 and will buy more. They stayed warm for 10 hours. Worked perfectly in Montana shooting college football outside.
Keeps me warm in negative windchills!
I missed that it was a single use…but I’ll still give it as a gift