This is a A-50X42 Sprocket PN: 50X42Main Description As Following : A-50X42 Sprocket P.N: 50X42 Hub Required: XInside Diameter: 2"Outside Diameter: 8.715"Teeth: 42 Crossed From: WSS105042 , , 3016-0213 , , 6713-52963 JOHN DAY , 673-S80504200 , , 673S80504200 , 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: 8.715" Teeth: 42