Item Type: Electric Hand WarmerMaterial: PC, aluminum alloySize: Approx. 112 x 60 x 24mm / 4.41 x 2.36 x 0.94inBuilt in Battery: Lithium battery, 5200mAhHeating Gear: 3 gears, 1st gear heating temperature 4550, 2nd gear heating temperature 5055, 3rd gear heating temperature 5560Package List1 x Hand warmer1 x USB Cable1 x Storage BagManual measurement with little error.1Portable: Small size makes the hand warmer easier to put in your pocket, and the warmth helps relieve menstrual cramps, chapped skin and frostbite. 2Perfect Gift: The perfect gift for sports enthusiasts, such as climbing, hiking, traveling, camping, skiing, cycling, etc. 3Safe to Use: Use high quality chipsets to control heat levels, no liquids and flame retardant materials to ensure product safety. 4Convenient Storage: Give you a portable bag for free, and put it in the bag when the high temperature makes you feel hot to avoid burns. 5Fast Heating: Using PC and aluminum alloy material, smooth touch, double sided heating keeps your hands warm at all times. 63 Gear Adjustment: 1st Gear heating temperature 4550, 2nd gear heating temperature 5055, 3rd gear heating temperature 5560, giving you more choices. 7Large Capacity Battery: Used as a mobile power source, built in 5200mAh lithium battery, which can fully charge digital devices, large capacity keeps warming hands for 48 hours, and recharges the phone 23 times.