If your toothbrush loses power quickly or doesn't hold charge, most likely the rechargeable battery is dead. Don't waste money on a new toothbrush system, including handle, brush head, and charger! Bring your old toothbrush to life again by replacing the dead battery.The battery is a brand new rechargeable Li-ION 3.7V 800 MAH battery, matching the original battery to ensure continuous successful operation. Long pins allow easy insertion through the circuit board holes in the tight battery compartment.Battery is fully tested before shipping. Due to the nature of battery product, NO return is accepted after it has been installed. Fits Philips Flexcare models: HX6710; HX6711; HX6712; HX6730; HX6732; HX6733; HX6902; HX6910; HX6911; HX6930; HX6932; HX6950;  HX6972; HX6982Li-Ion battery may catch on fire or explode if overheated or short-circuited. Make sure you handle it properly and carefully.