O-star 3.7V 600mAh 25C Lipo Battery(4PCS) with 4 In 1 X4 Battery Charger for Syma X5 X5C Parts 3.7V 600mAh 20C Lipo Battery(4PCS) with 4 In 1 X4 Battery Charger for Syma X5 X5C Parts Charging 4 battery at one time, Over charge protection, Short circuit protection Charger Voltage input: DC 5V; Voltage output: 4.2V  5%; Current output: 350mAh - 410 mAh