This is a A-50W15 Sprocket PN: 50W15Main Description As Following : A-50W15 Sprocket P.N: 50W15 Hub Required: WInside Diameter: 1 5/8"Outside Diameter: 3.316"Teeth: 15 Crossed From: WSS105015 , , 20005015 , , 20005015 , , 2827-39427 JOHN DAY , 3016-0186 , , 6713-51613 JOHN DAY , 673-S80501500 , , 673S80501500 , 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: 3.316" Teeth: 15