Hand Warmer adopts safe material and fine workmanship is sturdy and durable and has a comfortable hand feeling. Double-sided heating and 2 temperature levels Design, rapid heating and keeps hands warm in cold winter. With an integrated intelligent protection system, it is explosion-proof, safe to use. It can also be used as a 5000 mAH Mobile Power Bank for your mobile phone. Portable to carry, suitable for use in class, office, library, tea house, home, etc.