This is a A-B1G419 Sharpening Stones PN: B1G419Main Description As Following : A-B1G419 Sharpening Stones P.N: B1G419 Diameter: 7/32" Crossed From: 705-048 STENS , 705048 STENS Found in Section & Models : Sunbelt - Chainsaw & Forestry > Chainsaw Tools, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : A-B1G417, A-B1G418, A-B1G422, A-B1G721 Also This is An Aftermarket Product And : Aluminum oxide based abrasive on a 1/8" threaded shaft. Used on B1G721 grinder Pack of 3 Diameter: 7/32"