Energizer Premium Universal Charger. Charges all Energizer NiMH cell sizes: AA, AAA, C, D and 9V batteries. Charges batteries in about three to seven hours. Charger automatically shuts off when batteries are done. Trickle charge keeps batteries at full capacity. Charge LED status indicators tell you if batteries are charging or ready. Charger includes built-in safety timer to prevent overcharge, bad battery detection, short circuit/reverse polarity protection and delta V charging cut off. Power is only on when lid is closed. Energy Star certified.