The duracell ion speed 4000 nimh battery charger offers amazingly fast charge times of 1-2. 5 hours* with 4000 mw** of charging power. It recharges any rechargeable aa and aaa nimh battery from any brand. You can recharge 2 or 4 batteries at a time and, with the led charge status indicator, you’ll know when charging is complete. It also features an auto shutoff so you won’t use any unnecessary electricity. It even has a bad-battery indicator along with 9 smart safety features. Plus, the duracell rechargeable pre-charged nimh batteries are guaranteed to last 10 years***. *to approx. 85% of full charge when using 1300mah up to 2500mah 2xaa nimh batteries (included). **based on charging aa batteries. ***or 400 recharges, whichever comes first. Battery features the duracell ion speed 4000 nimh battery charger will recharge your batteries in 1-2. 5 hours* with 4000 mw** of charging power. With 4000 mw** charge power, duracell ion speed battery recharges batteries in 1 to 2. 5 hours. Auto shutoff: duracell ion speed battery charger has an auto shutoff feature, so you won’t use any unnecessary electricity. Multi-battery charge power: recharge 2 or 4 batteries at a single time with the duracell ion speed battery charger includes 4 batteries: battery charger comes with 2 double a and 2 triple a duracell rechargeable batteries.