Futaba AVCS GY401 Gyro (Only)This is the GY401 Gyro with SMM Technology from Futaba. This is a High Performance, Compact and Light Weight (AVCS) Angular Vector Control System gyro developed for model helicopters. Because the sensor and control circuit are integrated, it is simple to install. FEATURES: AVCS System: Since the rudder trim changes (caused by wind and other meteorological changes); the front, rear, and other heli attitudes change and are automatically cancelled; tail