These are nice, don't get me wrong, but I think they missed the mark. They heat up but the battery doesn't last very long and just hooking them to your boot usually ends in it hanging in your pants somewhere. Definitely buy the extension thingees so you can put them in your pant or coat pocket.

Keeps my feet always nice and warm

The first set of batteries didnt work and they were so helpful that sent me out a new package FOC!!

Love them

I am a skier, and adjust my boot settings frequently and ski aggressively. I lost a battery pack on the boot mounting syst. on the very first day of use. So much for $130 of expense. The replacement parts are very hard to find as the shops usually only carry hotronic replacement parts and thermic entire syst at orig purchase price w/out parts avail. I emailed thermic directly about my issues and never received an answer. Evidently they do not care about building customer loyalty. I also went back to the store where I bought them and their salesman said he has not received a response after multiple tries. I think I will go back to hotronic. I think Burton should pay attention to the service and parts policy of Thermic and reevaluate whom they wish to do business with.
Really wish I could give a better review.
Sonya