Rc helicopter applications outdoor indoor type of model rtf ready to fly propulsion electric special features gyro lighting led remote control included transmission mode radio number of channels 3 frequency range 2400 mhz transmission coverage 20 m type of battery lipo battery voltage 37 v battery capacity 250 mah weight 45 g length 250 mm width 50 mm height 120 mm rotor diameter 175 mm recommended minimum age 8 years colour green