Versatile D Batteries: The Artman 1.5V rechargeable lithium d batteries deliver optimal power to common every day office and household devices such as flashlights, radios, wireless microphones, camping lights, fans, gas stoves, toys, water heaters, etc USB Rechargeable Li-ion D Battery: No charger or adapter required, fast full charge in 2 hours with 2-in-1 USB-C cable. The D Li-ion battery built-in over-charge, over-current, over-voltage and short-circuit protection, no need to worry about security LED Charging Indicator: Easily monitor the d-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 rechargeable d batteries Rechargeable D Batteries: Rechargeable d lithium-ion 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, sa