[STANDARD 9V BATTERIES] - 9V rechargeable Li-ion battery can work with smoke detector/alarms, digital cameras, calculators, portable radios, microphones, toy remotes, clocks, flashlights, multimeter alarm systems, professional audio devices, guitar pedals/pickups, walkie-talkie, pencil sharpeners and other high drain electronic devices. Ideal replacement for the everyday 9V battery. [RELIABLE POWER] - 4-Pack 9V 550mAh rechargeable battery set provides more power for your equipment. Keep your device and tools running! [GREAT SAVING] - Don't use Alkaline batteries because they are not rechargeable! Our Li-ion battery can be used again and again after recharge so you don't have to keep buying new batteries! [SAFETY PROTECTIONS] - Integrated microchip prevents overcharging & lengthens battery life. Absolutely no memory effect so that you can charge battery at anytime [SERVICE] - USA Brand with Customer Service. Feel Free to contact us if you have any questions or concerns.