This is a A-B1OR534316 Sharpening Stone PN: B1OR534316Main Description As Following : A-B1OR534316 Sharpening Stone P.N: B1OR534316 511A, 109179Center Hole: 12mmDiameter: 145mmGrit: 3/8", .404"Material: VitrifiedReplaces: TL64Width: 4.5mm Found in Section & Models : Sunbelt - Blades > Blade Tools & Accessories, Oregon GRINDER, BLADE: 109179, Oregon GRINDER, BLADE: 511A, Sunbelt - Equipment > Grinders, Oregon GRINDER, BLADE: 109179, Oregon GRINDER, BLADE: 511A Associated Items : A-B1A2001100V Also This is An Aftermarket Product And : 511A, 109179 Center Hole: 12mm Diameter: 145mm Grit: 3/8", .404" Material: Vitrified Replaces: TL64 Width: 4.5mm