This is the Gear Set from Hitec. This works on the Hitec HS-755HB Servo.

FEATURES: Black karbonite construction Karbonite is a material stronger than plastic

INCLUDES: Complete gear set Four gears

REQUIRES: Assembly

COMMENTS: Instructions are not included dew1-6-05  

BOX DIMENSIONS: 2.38" W. X .75" H. X 3.00" L. BOX WEIGHT: .02 LBS.