Product Description60 tooth sprocket with 4-1/2″ drum for #35 chain. For Astro Wheel, comes with hardware. Also Fits vintage JD Enterprises wheels found on Mickey Thompson minibikes. Stamped for added precision, our one-piece #35 chain 60 tooth Steel Sprocket and 4-1/2″ Drum combinations provide strong, reliable units at economical prices. (Replaces Riveted assemblies.)The four bolt patterns are as follows:5 Holes for the Astro wheel3 holes (5/16″) on a 3.75″ Bolt Circle4 holes (1/4″) on a 3.75″ Bolt Circle4 holes (1/4″) on a 3.228″ Bolt Circle (these holes are differently spaced to accommodate the four holes on the mini-hubs AZ_2561 / AZ_2568 / AZ_2565)