Thermacell Heated Insoles are amazing foot warmers that offer convenient remote control operation. No wires or external batteries, and up to 2,500 hours of toasty heat to warm cold feet. Rechargeable heated insoles are great to wear in work boots, dress shoes, ski boots, loafers, sneakers any any other footwear that you own to provide hours of warmth. Feel the comforting heat with the touch of a button! Operated by a wireless remote control while the foot warmer is inside your shoes or boots Uses high-tech wireless thermal technology: no wires, cords, or straps Charge lasts up to 5 hours of constant use on medium heat Powered by rechargeable, built-in lithium-ion polymer batteries embedded in the foot warmer insoles Three temperature settings for comfort 1) No heat 2) Medium (100 degrees Fahrenheit 2) High(111 degrees Fahrenheit) Can be recharged up to 500 times using the included charger. About $0.25 per use or $0.05 per hour of use. ThermaCELL Heated Insoles Foot Warmers: Wireless Remote-controlled Rechargeable Lightweight Durable Whether you’re at work or play, cold feet are not fun. ThermaCELL Heated Insoles foot warmers keep your feet comfortably warm. They maintain a steady temperature inside your shoes or boots, keeping your feet around normal body temperature. That’s different from disposable chemical foot-warming pads that get hot to the touch and can make your feet sweat.