This is a A-40X40 Sprocket PN: 40X40Main Description As Following : A-40X40 Sprocket P.N: 40X40 Hub Required: XInside Diameter: 2"Outside Diameter: 6.653"Teeth: 40 Crossed From: WSS104040 , , 20004040 , , 20004040 , , 3016-0167 , , 6713-50913 JOHN DAY , 673-S80404000 , , 673S80404000 , 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: 6.653" Teeth: 40