Features:-With 2 LED indicators, when 1 is red and 1 is green, the battery starts charging. When both lights are green, the battery is fully charged.-The battery can be charged using any 5V USB port, such as PC, car charger, power bank, etc.-With a large capacity of 5200mAh, it has long-lasting power and can be used multiple times.-With multiple protections, short circuit protection, overheat protection, discharge protection, charging protection, over-voltage protection and magnetic field protection.-The shell is made of flame retardant material, which is resistant to high temperature and wear. The contact points are made of pure copper, which is not easy to oxidize and rust, thus avoiding poor contact.-For Ring Video Doorbell 2, Video Doorbell 3, Video Door.