Smatree Extended Battery(2500mAh) and Waterproof Backdoor for Gopro Hero 4, 3+ Smatree Extended Battery (2500mAh) for Gopro Hero 4, 3+ Camcorder with a Waterproof Backdoor And a Standard Backdoor Extended battery is rated at 3.8V and 2500mAh for a longer running time. Seamlessly attaches to the back of your camera to extend battery life with no memory effect. Displays battery level or charging status on both camera and battery. 3-year manufacturer warranty Package:1 x extended battery, 1 x ventilated backdoor, 1 x waterproof backdoor, 1 x MINI USB cord. Camera is not included.