Holy Stone 5 in 1 Fast Battery Charger(Max Current 2.5A Input) with 2 x UDI 818A 3.7v 500mAh Batteries 5 in 1 Battery Charger enable to fit for X5C X1 Holy Stone F180 M68 WLtoys Hubsan UDI 818A Voltage input: DC 5V; Voltage output: 3.7V; Current output: 500 mAh When the battery is charging, the light on charger lit. When finished, it will off automatically. Over charge protection and Short circuit protection Chargering batteries on the same time to enable your rc helicopter to have enough replaced battery so that to have longer flying time. Two 3.7V 500mAh Batteries for UDI 818A, 817,818, Hubsan,WL Toys