These are the Futaba Servo Horn Screws for the S9150 Digital Servo. These screws secure the horn to the splined output shaft of the servo. FEATURES: Keep extras on hand, or replace missing horn screws. Black in color, constructed of hardened steel for long life. INCLUDES: Ten Servo Horn Screws for the S9150 Digital Servo REQUIRES: Phillips screwdriver to install servo horn with screw SPECS: Length: 0.31" (8mm) Width: 0.11" (2.8mm)