Potensic Genuine 4pcs 3.7V 500mAh Batteries with 4 In 1 X4 Battery Charger for UDI U818A, U818A-1, U818A HD, U818A HD+ 2.4GHz 4 RC Quadcopter Official Battery from UDI U818A, U818A-1, U818A HD, U818A HD+. Batteries come equipped with built-in protection mechanism for safe charging and use. Enhance your flying experience by using only manufacturer recommended spare parts. Each battery provides 6-9 minutes of flying time, charging 4 battery at one time, Over charge protection, Short circuit protection. Rechargeable up to hundreds of times.