HuntHawk 3.7V 250mAh 25C Lipo Battery(4PCS) with 4 In 1 X4 Battery Charger for WLtoys V966 V988 Helicop, UdI U816 816A, Syma X11 X11C, Hubsan X4 H107C H107D H107L and Ladybird Charging 4 battery at one time, Over charge protection, Short circuit protection Compatible With: WLtoys V966 V988 Helicop, UdI U816 816A, Syma X11 X11C, Hubsan X4 H107C H107D H107L and Ladybird. Size of Each Battery: 37*18*7.5mm Package Included: 1* 4 in 1 Charger, 4* 250mAh batteries Chargering batteries on the same time to enable your rc helicopter to have enough replaced battery so that to have longer flying time.