This is the Futaba GY401 Gyro. This is a high performance, compact and lightweight (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 canceled; tail (rudder) operation is easy, making it perfect for 3D flight. (also known as heading hold gyro) SMM Gyro Sensor: Use of this newly developed technology virtually eliminates rudder trim changes during flight (see COMMENTS). Digital Servo Compatible (DS Mode): DS mode makes it compatible with Futaba digital servos. This maximizes the high-speed response performance of the digital servo. Included high-speed S9254 digital servo boasts 47 oz-in torque and a speed of .06 seconds @ 60° Remote Gain Function and Mode Switching Function Remote: Gain function allows sensitivity switching from the transmitter and mode switching function allows AVCS/normal gyro mode switching. Integrated, compact and lightweight design made possible by high density mounting technology. Conductive Resin Case: This case improves EMC (Electrostatic and electromagnetic interference) resistance. One year warranty INCLUDES: One GY401 gyro One mini plastic adjustment screwdriver Three mounting pads One instruction sheet SPECS: GY401 Gyro- Length: 1.1" (27mm) Hight1.6" (40mm) Width: 1.1" (27mm) Weight: 0.95oz (27g)