AA size Nickel-Metal Hydride (Ni-MH) 1.5volts, 2500mAh charges upto a 1000 times. 4 Batteries in a Pack AA size Nickel-Metal Hydride (Ni-MH) 1.5volts, 2500mAh charges upto a 1000 times. Commonly used in portable computers, Digital cameras, portable drills, and other small battery-powered devices, Far out performs alkaline batteries in high drain applications. NiMH batteries do not use heavy metals that may have toxic effects. In addition, they can store up to 50% more power than NiCad batteries and do not suffer from memory effects. This is where the battery seems to remember how full it was when last charged and will not charge past that point the next time