Thermacell Original Heated Insole

This foot warmer offers convenient remote operation, no wires or external batteries, and at least 2,500 hours of toasty heat to warm cold feet for about four winters of heavy use:

• Designed to keep your feet warm, not hot, to avoid having your feet sweat and freeze. They are not intended to get "hot" to the touch like disposable/ chemical foot warming pads. Rather, they will keep your feet comfortable and around normal body temperature.
• Rechargeable foot warmer is operated by a wireless remote control while the foot warmer is inside your shoes or boots
• Uses high-tech wireless thermal technology—no wires, extension cords, Velcro® straps, or battery strap brackets, and no batteries mounted to the ankle, shoe, or waist
• Charge lasts up to 5 hours of constant use (on medium heat setting)
• Powered by rechargeable, built-in lithium-ion polymer batteries embedded in the foot warmer insoles
• Adjustable to three temperature settings to warm cold feet by remote control: no heat, medium (100 degrees Fahrenheit), and high (111 degrees Fahrenheit)
• Can be recharged at least 500 times using the included charger.
• Recharges in 4 hours or less

Men's Sizing
Small: 3.5 to 5
Medium: 5.5 to 7
Large: 7.5 to 9
XL: 9.5 to 11
XXL: 11.5 to 13