These hand warmers feature safe material, double-sided heating, up to 15 hours of warmth, 3 heat levels, smart LED digital temperature display, 10000mAh power bank, and compact portable design. Suitable for those with Raynauds and arthritis, this is an eco-friendly and cost-effective hand warmer that brings warmth from fingertips to heart. Features 1. Safe Material: The warmers' surface is made of high-tech aircraft-grade aluminum and ABS with excellent thermal conductivity, tight density, and drop-proof. Enjoy the comfort and warmth that comes with safety. 2. Double-sided Heating with 2s Instant Heat: This rechargeable hand warmer adopts a 10000mAh high-efficient battery, letting it warm for 15 hours (the exact heating time, depending on the heat level you choose and the environment temperature). The 2 seconds quick double-sided heating design will warm you up faster and keeps you warm all day. These rechargeable hand warmers can be reused more than thousands of times, saving money and environment friendly. 3. 3 Heat Level with Smart LED Digital Temperature Displa: There are 3 precise levels of heat to choose from (104F/40C, 122F/50C, 140F/60C) by a simple button; Long press the power button to turn it on, short press to change the heating level, the LED digital temperature display will let you know which heating temperature is suitable your palm well. 4. 10000mAh Large Battery Capacity Power Bank: The USB handwarmers also works as a portable charger when your electronic devices are out of power. Also, it is an excellent gift for women, men, elderly who with Raynauds, arthritis, and need heat therapy. This handwarmer will bring the warmth from your fingertip to your heart. 5. Compact and Portable: Portable palm-size pocket hand heater is equipped with a liquid lanyard, which is easy to carry and not easy to fall. The size of the electronic hand warmer is 4.33 x2.75 inch, smooth and easy to hold, you can put it in your pocket or you can also put them in your bag, and easy to take it anywhere, use it any-time you want. Specification Material: ABS Color: Black, Pink, Green Size: 11 x 7 cm Weight: 241 g Battery Capacity: 10000 mAH Rated power: 3.7W Package Include: 1x Hand Warmer