I'm in minnesota and have always had cold feet while hunting. I didnt want to spend $100+ only to have them not work. I got a cheaper pair off amazon and they've lasted two seasons. The batteries last between 3-6 hours depending on which setting you use. I usually wear a mid-weight wool sock under them and am really happy with how well they work.

Autocastle Electric Heated Socks Rechargeable Battery Heat Sox Kit for Men Women,Unisex Winter Warm Battery Powered Heating Thermal Stockings,Novelty Sports Outdoor Heated Socks Hunting Foot Warmer https://www.amazon.com/dp/B075M72BXZ/ref=cm_sw_r_cp_apa_i_cqg0DbBPBP31Q