GL500 II Radio remote control RC helicopter ARF (80% assembled) aluminum case package Length: 1114mm Height: 288mm Main rotor diameter: 980mm Tail rotor diameter: 165mm Main rotor length: 430mm Main drive gear: 120T Motor drive gear: 18T/20T ECS: BL 80A Motor: KDS-WS-3648 1100KV Recommended Equipment Battery for receiver: 7.4 V, 1000~1200mAh Power battery: 22.2V 15C 3300mAh or more ( or 2 pcs of 11.1V 2200mAh 15C battery) Transmitter: 6channel or more Servo: FUTABA S3150 S9650,Hitec HS-85MG or others. Rud servo: S9254,S9253, 9650, 9257 or other similar ones