This Watson 4-Hour Rapid Charger comes with four 1.2V, 2300mAh AA NiMH batteries that are rechargeable up to 1000 times. The charger will recharge 4 of these included batteries in about 280 min, or 2 in about 140 min. You can also use it to charge optional AA NiCd batteries, or AAA NiMH or NiCd's. The charger's integrated micro-controller ensures that each battery is charged to its full capacity, and automatic charge cut-off prevents overcharging. Should the controller and automatic cut-off function both fail, the safety guard timer will kick in to ensure that the charger still shuts off after 6 hr. The charger also has circuit and polarity protection. Two LED indicators display charging status, and there are two individually-monitored charging channels. The charger has switching 100-240VAC power, enabling use all over the world. Its compact outlet prongs can fold in, making the unit more compact for storage.