This is a A-IHX58 X Hub, Idler Hub PN: IHX58Main Description As Following : A-IHX58 X Hub, Idler Hub P.N: IHX58 Bore: 5/8" Crossed From: WSH3B3010 , Found in Section & Models : Chains/ Sprockets/ Pulleys/ Hubs > Hubs, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also This is An Aftermarket Product And : Bore: 5/8"