Made of 6061 aircraft aluminum for maximum strength.the spline is a hardened steel insert for super long life. 25 spline.Fits Savox, Protek, Futaba, Radio Post servos
Please be aware that the fit is sometimes a little snug if you are putting this unit on a used servo.
If you experience this you may have to put the unit on and off a few times to get the splines on the servo to free up and conform to the steel insert.
