Part Number and Specifications 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 If needed, reducing stud bushings are also available separately. 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. Finished with silver anodizing for durability and corrosion resistance. There is so much riding on these components, it’s worth using the best parts available. Backed by The Chassis Shop's Satisfaction Guarantee. You can always count on Pro-Werks to do it right!