These short solid replacement pucks are sold separately and work on specific bikes. The frames on these bikes are very close to the bodywork, so Woodcraft developed a shorter puck for race purposes.  They are 1/4" shorter than the standard replacement pucks.  It's a good idea for racers to carry a spare in the toolbox.  They are replaced with the single perpendicular bolt.

This is a single replacement puck only.

Note: These low profile pucks are recommended for racing use on many models and Ducati under bodywork sliders.