Futaba S3157 Digital Micro Hi-Speed/Torque Servo FEATURES: Ideal for small electric planes and helicopters INCLUDES: Futaba S3157 Digital High Speed/High Torque Micro Servo with universal Connector .71 x .79 (18mm x 20mm) 4 arm servo horn (pre-installed) REQUIRES: Installing in aircraft, Connecting linkage and Connecting to receiver Order DUBM6924 if mounting hardware is needed