13500 mAh Powerful BatteryNS04 Rechargeable Hand Warmer has the largest battery capacity on the market. It can support 7-16 working hours after being fully charged. The power bank function can also charge your mobile phone for emergencies. 3 Fast Heating LevelsElectric Hand Warmer adopts constant temperature heating technology, which can heat up quickly in 3 seconds. There are 3 different heating levels to meet your needs [104 (40)], [122 (50)], 140 (60)]. LED Digital DisplayUSB Reusable Hand Warmer can display the heating temperature and remaining power in real-time for user-friendly. Safety PriorityHand Warmer is carefully selected with high-quality materials and a built-in intelligent protection system to prevent overheating, overcharging, short circuits, and explosion risks. It is UL, CE, FCC, RoHS certified. More Details & Gift ChoiceSilicone corner protection against falls, USB Type C port dust plug protection, portable pocket size with lanyard, suitable for golf, football, fishing, hiking, camping, etc. These thoughtful little details make it perfect as a winter gift choice for Christmas, Thanksgiving Day, Valentine's Day.