2.4Ghz 4CH RC Helicopter Auto rudder trimming 4 in 1 controller (receiver, flight control system, gyro, mixer) 2.4Ghz 4CH Coaxial Rotor ... )Feature:Auto rudder trimming450mAH 15C LiPo Battery4 in 1 controller (receiver, flight control system, gyro, mixer)Durable CNC Alloy ChassisCNC Machined ... 20-80%,servo reverseMicro 2g servosUSB Charger 2.4Ghz 4CH RC Helicopter