Bad Battery Detection Audio and LED charging status indicators Automatic switch-off Reverse polarity detection Universal voltage (AC 100-240V) Charges 2-4 AA or AAA NiMH batteries at a time Approx. Charging time AA: 1300-2000mAh – 3-4 hours 2000-2400mAh – 4-5 hours Approx. Charging time AAA: 500-800mAh – 3-4 hours