Recharge your batteries in 4-8 hours (to approx. 90% of full charge when using 1300mAh up to 2500mAh 2xAA NiMH batteries, included) with 1000 mW of charging power (based on charging AA batteries). It recharges any AA and AAA NiMH batteries from any brand. You can recharge 2 or 4 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. Batteries are guaranteed to last 10 years, or 400 recharges, whichever comes first.