This is a A-50W13 Sprocket PN: 50W13Main Description As Following : A-50W13 Sprocket P.N: 50W13 Hub Required: WInside Diameter: 1 5/8"Outside Diameter: 2.911"Teeth: 13 Crossed From: WSS105013 , , 20005013 , , 20005013 , , 2827-39327 JOHN DAY , 3016-0184 , , 6713-51513 JOHN DAY , 673-S80501300 , , 673S80501300 , Found in Section & Models : Chains/ Sprockets/ Pulleys/ Hubs > Sprockets, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also This is An Aftermarket Product And : Hub Required: W Inside Diameter: 1 5/8" Outside Diameter: 2.911" Teeth: 13