Rechargeable NiMH Batteries with Duralock Power Preserve TechStayCharged™ rechargeables come fully charged and ready to be used right out of the package. Recharge up to 400 times--save hundreds of dollars. Stays charged for up to one year. Ideally suited for high-drain and frequently used devices. Battery Type: NiMH Rechargeable; Battery Size: AA; For Use With: Everyday Electronic Devices.