Celestron Elements ThermoCharge Hand Warmer & Power Pack 2-in-1 device: portable power pack and hand warmer 4400 mAh rechargeable battery provides 6 hours of continuous heat Charges smartphones, MP3 players, cameras and many other USB-powered devices Durable, aluminum housing with protective silicone caps Ergonomically designed to fit easily in your pocket or bag Includes USB charging cable and soft carry pouch