This is a A-50X40 Sprocket PN: 50X40Main Description As Following : A-50X40 Sprocket P.N: 50X40 Hub Required: XInside Diameter: 2"Outside Diameter: 8.316"Teeth: 40 Crossed From: WSS105040 , , 3016-0211 , , 6713-52863 JOHN DAY , 673-S80504000 , , 673S80504000 , 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: 8.316" Teeth: 40