New 72 tooth zinc plated steel sprocket for #35 chain with 6 lightning holes. 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.Used on 6" Astro wheels and others with that bolt pattern. overall height is 8-3/4". Install on your every day rider or restoration.