This is an optional EcoPower Aluminum Clamping Servo Horn, intended for use with EcoPower servos along with other 25T splined servos. This extremely tough servo-horn has been machined from a solid block of aluminum for incredible precision, rigidity, and durability. The horn features a clamp type design that grips the servo’s output shaft so if the retainer screw comes loose, the horn will have a better chance of remaining in place, increasing your chances of finishing the race!