Part C44-001 and C44-0030.702 in. Hole Diameters3-1/16 in. Center Hole Part C44-005 and C44-0070.702 in. Hole Diameters3-1/2 in. Center Hole Part C44-013 and C44-0150.702 in. Hole Diameters4-1/4 in. Center Hole Part C44-017 and C44-0190.531 in. Hole Diameters4-1/4 in. Center Hole Part C44-021 and C44-0230.578 in. Hole Diameters5-1/8 in. Center Hole Finished with silver anodizing for durability and corrosion resistance. Billet Wheel Spacers The Pro-Werks billet aluminum wheel spacers are precision CNC machined for proper fit and parallelism. This is a more accurate means of production than competitor’s mass-produced die-cut, laser or water jet methods. It takes a little more to make them correctly - but we think you will appreciate getting a great product for your hard earned dollar. Available in several bolt patterns and both 1/4" or 1/2" thicknesses. If needed, reducing stud bushings are also available separately. You can count on Pro-Werks to do it right !