Volt Heated Socks Polyester/Spandex Imported Provides up to 10 hours of soothing warmth to help rejuvenate numb toes and cold, tired feet Firm, comfortable fit Four power level settings allowing you to select your desired heat output Provides up to 10 hours of soothing warmth to help rejuvenate numb toes and cold, tired feet Firm, comfortable fit Four power level settings allowing you to select your desired heat output