DMT Diamond Sharpener 7/8 inch x 4 inch x 3/16 inch. Extra-Fine (9 micron / 1200 mesh) to polish and refine a razor edge after sharpening with a coarser diamond. Grit clearly marked on side of stone. The Dia-Sharp(R) 4 inch continuous diamond sharpening stone delivers full-size sharpening while maximizing work and storage space.