Stand alone bushing bore adapters for 17mm ID (6203-2RS, serpentine idler pulley or other 12mm wide) bearings. These include bushing bore adapters, shoulder adapters, and clevis (double shoulder) adapters. Made from sintered steel with light oil. They are press fit; make sure you support the bearing when installing. If you are buying pulleys, you do NOT need to buy these, simply select the adapter you need from the pulley page.