Functions: This Electrical hand warmer is great for keeping those winter chills away, simply is charged for few minutes, you will have instant heat for around 2-4 hours. Ideal for all cold weather activities, . It has health protection function and good treatment for arthritic. features: 1. Feel specially soft and magic. 2. It can keep warm for about 2~4 hours once charging. 3. To recharge it again when it is cool, you just plug on the electric power for a few minutes. And it is automatically shut down when it reaches the required temperature.?4.The temperature of warmer can reach 65~70 degree celsius. 5. Not necessary to refill water.