Versatile C Batteries: Lithium C batteries are compatible with LED flashlights, emergency lights, wireless toys, electronic pianos, remote controls, radios, stereos, clocks, cameras, trash cans, toys, baby swings, smoke alarms, wireless speakers, etc USB Rechargeable Lithium C Battery: No charger or adapter required, fast full charge in 2 hours with 2-in-1 USB-C cable. The C Li-ion battery built-in over-charge, over-current, over-voltage and short-circuit protection, no need to worry about security Rechargeable C Batteries: Rechargeable USB C lithium batteries with up to 9000mWh capacity last 3-5 times longer than regular alkaline batteries and have no memory effect, recharge up to 1200+ times when fully or partially depleted, saving you money LED Charging Indicator: Easily monitor the C-cell battery charging status with the LED indicator. It will flash blue when charging and turn into a solid blue light when fully charged, ensuring you always know the status of your C batteries