Electric Hand Warmer with Double Temperature Controller and 5 to 8 Minutes Recharging Time Double-security: A double temperature controller is incorporated to realize double-security so that users can rest assured during using When temperature reaches about 60°C, it will automatically switch off In case of either a temperature controller broken, the other expansion controller will begin to operate If temperature controller does not work and the temperature is up to 90°C, the expansion controller will start to expand and break both electrodes so as to shut off the power supply As the external material is double-layer and high elasticity imported PVC, it can not only guarantee enough space for expansion during charging, but also will prolong the period for heat preservation Quickly recharge: only five to eight minutes to recharge Prolonged using time: one charge can support hand warming for 3 hours and keep warming for 12 hours The product has been enveloped firmly along the circumference so that it can maintain its appearance intact and will not be worn or broken even after being used for a long time An indicator lamp can guarantee safety