Astak Digital Ultra-fast Battery Charger for Ni-MH, Ni-Cd, 4 AA ,4 AAA Battery With Car Charger Plug /Wall Charger Plug, Overcharge Protection, Microprocessor Controlled Recharge 2 or 4 pieces of AA, AAA Ni-MH / Ni-Cd batteries in 2-3 hours Powered by an external AC adaptor for indoor use or by a car cigarette lighter plug from 12V DC car battery while you are travelling Intelligent microprocessor controlled Identification of defective batteries With negative delta V Cut off feature to 100% protect your batteries