Feature: 1. Mini Body Shape: It makes it easier to put warm hands in your pockets. Warmth can help relieve menstrual periods, chapped skin and frostbite. 2. Safety: Use high quality chipsets to control heat levels, no liquids and flame retardant materials to ensure product safety. Give you a storage bag for free, and put it in the bag when the high temperature makes you feel hot to avoid burns. 3. Fast Heating In 3 Seconds: Glossy touch, double sided heating keeps your hands warm at all times, creating a warm world for you in winter. 4. Used As Mobile Power Source: The rechargeable hand warmer has a built in 4000mAh lithium battery, which can fully charge mainstream digital devices on the market. It has a large capacity to keep your hands warm for 3‑5 hours, and it can charge the phone 1‑2 times. 5. Adjustable Temperature: 3 different heat levels can be adjusted freely, one heating temperature is 47‑52℃, and two heating temperature is 55‑60℃. Specification: Item Type: Hand Warmer Product Material: Plastic, Silicone Product Efficacy: The Mini Body Shape Makes It Easier To Put The Hand Warmer Into The Pocket, And The Warmth Helps Relieve Menstrual Period, Skin Chapped And Frostbite. Power Supply Mode: Usb Plug In Battery Type: Lithium Battery (Shipped With Built in Battery) Battery Capacity: 4000mAh. Package List: 1 x Hand Warmer1 x USB Data Cable1 x Conversion Head1 x User Manual1 x Storage Bag