About this item IN THE BOX: 4-hour Ni-MH battery charger for AA and AAA rechargeable batteries EASY & EFFICIENT: Unit plugs into an AC wall outlet; recharges 2 or 4 AA or AAA Ni-MH batteries at a time (batteries must be charged in pairs; never use non-rechargeable batteries) CHARGES USB DEVICES: USB port (maximum output 500 mA) for charging a smartphone, iPod, or other handheld device TRAVEL FRIENDLY: Flip-down plug with a slim profile and switching power ability for worldwide use (100 to 240 AC) SAFETY FEATURES: Wrong polarity protection and cut-off function to prevent overcharging DIMENSIONS: 4.5 x 2.75 x 1.5 inches (LxWxH)