New 60 tooth #35 chain zinc plated steel sprocket. The 5 mounting holes are drilled for 5/16" bolts at 1-3/4" centers. Center hole is drilled 1-3/8" so bearing fits inside to better line up the rear axle. Can be used on the Astro wheel and other wheels with that bolt pattern. Overall height is 7-1/4". Perfect for Ruttman, lil Indian, and many others. Install on your every day rider or restoration.