This is a A-40X28 Sprocket PN: 40X28Main Description As Following : A-40X28 Sprocket P.N: 40X28 Hub Required: XInside Diameter: 2"Outside Diameter: 4.738"Teeth: 28 Crossed From: WSS104028 , , 20004028 , , 20004028 , , 3016-0156 , , 6713-50613 JOHN DAY , 673-S80402800 , , 673S80402800 , Found in Section & Models : Chains/ Sprockets/ Pulleys/ Hubs > Sprockets, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also This is An Aftermarket Product And : Hub Required: X Inside Diameter: 2" Outside Diameter: 4.738" Teeth: 28