USB CHARGE DESIGNNo need charger and adapter,fast full charge in about 2 hours,easy to charge with usb cable, just simply plug into USB ports LED INDICATORS MANAGEMENTWhen charging, the LED will hold on red; when fully charged, the LED will remain green. DITCH DISPOSABLE BATTERYRechargeable usb C battery with 1000+ cycles , save your big money comparing with the single use batteries. MULTIPLE SAFE PROTECTIONBuilt-in Integrated safety circuit protects Battery from over discharge/overcharge,when the battery is fully charged, it will automatically stop charging,passed the test of CE, ROSH, 2006/66/EC. ENERGY SAVINGMercury, cadmium and lead are not used in these lithium c rechargeable batteries, saving thousands of alkaline batteries and reducing a significant about of landfill waste.