Made of high strength aluminum, corrosion protected by anodize, set of 2 pieces including mounting material. Sold as a pair. Choose 10, 15 or 20mm. 10mm and 15mm spacers come with longer bolts. 20mm spacers come with bolts to mount the spacer to the hub and then the factory wheel bolts are used to mount the wheel to the spacer. NOTE: Retaining bolt and lineup pin must be removed for install.