With patented TurnLOCK, changing bushings is tool free, hardware free and takes only seconds. Guide bushings lock into position with just a simple twist. Base plate is made of durable, clear polycarbonate. Special ride pads keep your router base scratch free. Base plate systems include: base plate; centering pin; mounting hardware; detailed instructions, and corresponding 9-piece guide bushing set. Guide bushing sets are molded from reinforced ABS resin. Metal nose bushings are for high-wear applications. Each guide bushing set includes eight sizes of guide bushings: 5/16",3/8",7/16",1/2",5/8",51/64", and 7/16" and 5/8" Extended Nose. and Porter-Cable style guide adapter.