YXZNRC F11 AH-64D Apache 6-Axis Gyro 6CH 3D Aircraft RTF RC Helicopter 2 Battery. YXZNRC EC135 6CH Gyro 2.4G Flybarless Optical Flow Altitude Hold RC Helicopter. Optical Flow Positioning: Adopting LIDAR+Lower Visual Optical Flow Positioning System, which makes the height more stable and a ccurate.
