EZELAP Diamond Products 2-1/2" x 11-3/8" x 3/8" Diamond Stones These diamond stones are perfect for hunting and fishing knives, woodworking tools, exacto blades, axes and industrial use. No oil or water is necessary, the surface will remain true and flat. Model 121 2-1/2" x 11-3/8" X 3/8" Diamond Stone designed to fit in Tri Stone Holders Model Description 121SF Super Fine Grit (1200) 121F Fine Grit (600) 121M Medium Grit (400) 121C Coarse Grit (250) 121XC Extra Coarse (150)