This is a A-40X27 Sprocket PN: 40X27Main Description As Following : A-40X27 Sprocket P.N: 40X27 Hub Required: XInside Diameter: 2"Outside Diameter: 4.578"Teeth: 27 Crossed From: WSS104027 , , 20004027 , , 20004027 , , 3016-0155 , , 6713-50563 JOHN DAY , 971-20004027 , , 97120004027 , 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: 4.578" Teeth: 27