Duracell® ION SPEED™ 4000 Hi-Performance Charger Charges batteries in 1-2.5 hours with 4000 mW charge power. (To approx. 85% of full charge when using 1300mAh up to 2500mAh 2xAA NiMH Batteries (included). Based on charging AA batteries.) Comes with 4 premium AA Duracell Rechargeable Pre-Charged batteries that are 50% longer-lasting per charge* and guaranteed to last 10 years.** (*vs. 1350mAh within the first 200 cycles. **Or 400 recharges, whichever comes first). LED Charge Status Indicator shows when charging is complete and Auto Shutoff when batteries are charged. This battery charger works with all rechargeable AA and AAA NiMH batteries.