A Professional Range precision double-sided credit card size diamond stone. Fine 600 grit (25 micron) Coarse 300 grit (50 micron). Complete with black storage wallet. Guaranteed for five years when used with Trend Lapping Fluid. Ideal for fluted, shaped & small router bits, carbide or HSS, turning tools, chisels, plane blades, carving tools & all general tooling. Plate thickness 1.6mm for extra stability. Grit sizes clearly marked on each surface. Specifications Type or Grade: 600/300 grit