This is a A-40X54 Sprocket PN: 40X54Main Description As Following : A-40X54 Sprocket P.N: 40X54 Hub Required: XInside Diameter: 2"Outside Diameter: 8.885"Teeth: 54 Crossed From: WSS104054 , , 20004054 , , 20004054 , , 3016-0177 , , 6713-51113 JOHN DAY , 971-20004054 , , 97120004054 , 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: 8.885" Teeth: 54