Charges 2-4 pieces of AAA AA batteries Negative delta V detection switches off charger immediately the batteries are fully charged Timer control Trickle charge function keeps batteries topped up when fully charged Overcharge short circuit & reverse polarity protection Faulty battery detection Low battery leakage current Pulse charging function LEDs indicate charging status of each individual battery Worldwide voltage range 100V-240V subject to use with a suitable travel adaptor 5-8 hours average charge time