Conveniently charges (4) AA or AAA NiMH rechargeable batteries at the same time. 3 to 5 hour charge time with auto shut-off to prevent overcharging and battery damage. The charger is equipped with audio and visual alerts. A red light means that charging has started, and you will hear an audible beep when charging begins. A yellow light appears when charging is 50% complete and charging is continuing. A green light means charging is complete, and the batteries are 100 percent full. You will hear an audible beep upon completion. If a bad battery is detected, a red X will illuminate, and the charger generates a repetitive audible beep upon detection. Includes (4) AA batteries.