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 & no batteries mounted to your ankle, shoe or waist * Lithium ion polymer batteries embedded in the foot warmer insoles are rechargeable * Adjustable to three temperature settings to warm cold feet by remote control: settings are no heat, medium 100 degees & high 111 degrees * Recharged up to 500 times