This is a A-50X50 Sprocket PN: 50X50Main Description As Following : A-50X50 Sprocket P.N: 50X50 Hub Required: XInside Diameter: 2"Outside Diameter: 10.309"Teeth: 50 Crossed From: 3016-0219 , , 6713-53213 JOHN DAY , 673-S80505000 , , 673S80505000 , 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: 10.309" Teeth: 50