SAVEoN Battery and Charger Kit for Nikon SB-600 Speedlight Flash includes 4 AA High Capacity NiMH Batteries + 2 Hour AC/DC Charger (charges AA/AAA batteries) + SAVEoN MicroFiber Cleaning Cloth This unit will charge your batteries in 2 hours. Charger completely before first use. Subsequent partial charges will NOT reduce batteries' capacity through memory buildup, unlike conventional NiCD batteries Charges 2 or 4 Batteries at a time. When charging 2 batteries, pt them in the left two channels. LED lights will be while charging batteries and will turn green when filly charged. Batteries Life well protected by negative delta V Cut-off function and timer protection Temperature sensors prevent the battery from being damaged by overheating. Battery features - 100% memory free, lasts up 4x longer than regular batteries. Charges up to 1000x Specifically engineered for High Drain Devices. NiMH Technology recommended by digital camera manufactures