This is a A-40X45 Sprocket PN: 40X45Main Description As Following : A-40X45 Sprocket P.N: 40X45 Hub Required: XInside Diameter: 2"Outside Diameter: 7.451"Teeth: 45 Crossed From: WSS104045 , , 20004045 , , 20004045 , , 3016-0172 , , 6713-51013 JOHN DAY , 673-S80404500 , , 673S80404500 , 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: 7.451" Teeth: 45