This is the Gear Set for the Futaba S9451 Digital Servo. These gears transfer movement from the motor to the servo horn. FEATURES: Replaces worn or damaged gears INCLUDES: One nylon 1st gear One steel and brass 2nd gear One steel and brass 3rd gear One steel 4th or final output gear REQUIRES: Installing in servo case. COMMENTS: For the Case Set, use FUTM3069 1/25/03 mcw ir/jxs