This is a A-40W17 Sprocket PN: 40W17Main Description As Following : A-40W17 Sprocket P.N: 40W17 Hub Required: WInside Diameter: 1 5/8"Outside Diameter: 2.975"Teeth: 17 Crossed From: WSS104017 , , 20004017 , , 20004017 , , 2827-38027 JOHN DAY , 3016-0145 , , 6713-50063 JOHN DAY , 673-S80401700 , , 673S80401700 , 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: 2.975" Teeth: 17