Review on Stay Warm This Winter With Rechargeable Electric Socks: Unisex Battery Powered Insulated Heat Kit For Skiing, Biking, And Hunting by Sam Bell

Just wore the socks in CO for 5 days of skiing in 30 degree weather. Put them on low and they lasted all day. Never once thought about my feet, which normally ache in the cold. Not sure if low would be enough to last all day on those few -5 degree days. I will probably buy a second set so that I can use both sets of batteries on super cold days and to swap the socks out for washing. Recommended.