These are replacement bushings for the new Perfect Raceway Tool, Version 2.0, Engineered Composite speed tool.
Simiply snap out the existing bushings and snap these new Delrin, High Speed, High Temperature bushings into the holes.
Bushings are engineered to snap in and remain in place. Some effort may be required to insert them correctly. Make sure you place them back in the same orientation as those you are replacing.