This Duracell Ion Speed 4000 NiMH Battery Charger offers amazingly fast charge times of 1 to 2.5 hours (To approx. 85% of full charge when using 1300mAh up to 2500mAh 2xAA NiMH Batteries) with 4000 mW of charging power. It recharges any rechargeable AA & AAA NiMH battery from any brand. You can recharge two or four batteries at a time and, with the LED Charge Status Indicator, youll know when charging is complete. It also features an Auto Shutoff so you wont use any unnecessary electricity. It even has a bad-battery indicator along with nine smart safety features. Plus, the Duracell Rechargeable Pre-Charged NiMH batteries are guaranteed to last 10 years or 400 recharges, whichever comes first. Battery Type: NiMH; Battery Size: AA; AAA; Charge Time: 1 to 2.5 h.