Electric hand warmer

Electric hand warmer 1.Automatic power-off 2.Explosion proof 3.Take 8-14 minutes to heat up only,which can keep warming hand for 2 hours and warming quit for 6Hours 4.Explosion proof.In case of breaking,the other explosion controller will begin to operate.When the temperature is up to 90 degree,the expasion controller start to expand and break both electrodes so as to shut off the power supply. 5.Quality is reliable.The warm bag is made of ultra-strong rubber film composite fiber.The heating medium is used to heat up the heating element and reserve the energy.