7" Remote Controlled Walkera New 4 Channel Mini Helicopter RTF Main rotor Dia. (Upper): 175mm,Main rotor Dia. (Lower): 175mm,Overall Length: 180mm ,Drive System; 2 x 1215 strong-magnetic motor Servo: weight 3.5g;speed 0.11sec/60o(4.8V);torque 0.30kg/cm(4.8V) Coaxial structure and palm-sized dimension are used to make HM 5G6 as the optimal model for indoor entertainment 2 x 1215 strong-magnetic motor as power is powerful and makes flight stable Highly efficient servo (3g) is prompt in reaction and effectively guarantees the performance of various flights