This 0.500" OD, 1" length Servo Shaft is one of several integral parts of a ServoBlock. The 0.500" outside diameter provides an excellent surface to install a bearing onto in order to isolate radial load from being applied directly to the spline of your servo. To fasten components onto the servo shaft you can then install a 1/2" clamping hub to provide a non-marring, super strong connection. By using the combination of this servo shaft and a clamping hub instead of the Actobotics Servo Hub Shaft, you can easily index the mating component or remove it and re-install it without having to remove any fasteners - just loosen the pinch bolt on the clamping hub. The center bore provides easy access to allow you to install the stock servo screw which will hold the servo shaft down onto the servo. The 0.500" Servo Shafts are offered with the 24 Tooth (C1) Spline or 25 Tooth (3F/H25T) Spline which means they're compatible with most servo brands on the market. Patented.