Noiposi 4Pcs 3.7V 780mAh 20C Lipo Battery with X4 Charger for Wltoys V636 V686 V686G V686K JJRC V686 Rc Quadcopter drone Model number :3.7v 780mah 20C and X4 charger Charger Voltage input: DC 5V; Voltage output: 4.2V ,charging 4 battery at one time ,over-charge protection and Short circuit protection Product size:50*30*6mm/1.97*1.18*0.24 in Red Lights on: currently charging ;Red Lights off: charging completely lease make sure that the size of the battery is suitable for your drone before purchasing!