Universal 1 Hour Fast Charger This universal 1 hour fast Charger is designed for use with NiMH (nickel Metal Hydride) AA /AAA/C/D/9V cells commonly used in todays digital camera, MP3, CD players, radios, and other electronic devices Batteries will self discharge when not in use. Batteries can be kept fresh if you recharge them every 2-3 months Plugs directly into any AC outlet Unique battery box design that makes it serves as a storage case for batteries when it is not in use