I too froze my feet when young have tried the old version heated socks twice{reg batteries} they did not last long at all.
3 years ago I bought the Therma Cell heated insoles with removable battery pack and a spare set of Batteries. For me they work great both hunting and ice fishing.
Only downside is hiking in to stands the battery pack in the heal is hard Easily remedied by swapping liners over once I get into my spot. Only missed one shooting opportunity from performing this task
