The Grabber Mycoal 12+ Hour Warm Pack pocket warmer (10 Pack) is a multi-purpose, portable heating pad you can place in mufflers, pockets and more, providing soothing comfort for minor aches and pains, as well as warmth during outdoor winter activities.
Features
Clean, odorless, dry and non-toxic heat source
More than 12 hours of reliable heat
No kneading or shaking necessary
Creates minumum temperature of 104-degrees Fahrenheit, average temperature of 135-degrees F, and maximum temperature of 166-degrees F
Used these on cold mornings while working outside. They did not heat up quickly, they did not warm up as the packaging said that they would, and they certainly didn't last 12 hours. We were very disappointed in this item.
Under the multi pack review I've desrcibed one good use for this produce. Can't wait to try these heaters for warming the sleeping bag, but won't get that coance for a few months yet. Based on the way I've used it before, it should work realy well.
EXCELLENT! Used them for the first time in the desert where the over night temps were around freezing. Used two in my sleeping bag but only needed one. Put one on my stomach, pulled it out and put it between my skin and "night-shirt" because the pack got a little too warm! It helped warm my entire trunk and made all the difference in the world. Going to buy some more. The pack stayed warm all night and the next morning I put the still "kind of warm" packs in my pockets to hike with. Give them a try!