…do not work. I tried twice last week and they suck. They are designed to be worn inside boots and were ice cold when I took my waders off and then warmed up again once they hit air. Save your cash.
They make a chemical warmer that is real weird – it’s a plastic baggie full of gel that you warm in warm water or microwave or something to “set” it, then when you want heat you just click this little magnesium disc inside the gel back and forth and it makes some kind of chemical reaction begin – the heat pack becomes a crystalline solid and gives off heat.
Bill, I should have said they suck in waders. The package does say that they are supposed to work with limited air and are “ideal for fisherman”, they are not. I have not tried them in regular boots but, they do stay warm for a long time fully exposed to air. I will save a “totaly suck” conviction until I try them further.