Outside diameter: 1"/25.4mm Inside diameter: 3/8"/9.52mm (fits 3/8" or M10 bolts) Length: Varies-Choose Length Shape: Round Material Type: T-6061 Aluminum with tumbled aluminum finish Metal Spacers Online provides many sizes of round aluminum spacer, bushings, standoffs and washers. Our aluminum spacers are either milled or extruded for a quality smooth finish. Before checking out, choose the length of spacer and the package quantity to insure you are getting what you need. This listing is for a specific inside and outside diameter, you can visit our Amazon store to browse all of our other sizes that are available, you are sure to find what you need there.