This more economical series spacer is the same material as the Urethane EZ Fit. The difference lies in the mounting procedure. These spacers require the removal of the press-in studs. Long hex bolts insert through the holes, spacers and wheels. In order to tighten, the head of the bolt must be accessed. These spacers will not work where the head of the bolt is hidden and/or inaccessible, such as what might be encountered on some four wheel drive models. You must use the EZ Fit for these machines. NOTE: Graph-lite "GL" spacers require that the studs be removed from the hub for installation and long "through bolts" (supplied) inserted in the stud hole