Trend DWS/CC/FC Fine/Coarse 3-Inch Double-sided Diamond Credit Card Stone Double sided stone has fine 600 grit (25 micron) for razor sharp edges and coarse 300 grit (45 micron) to bring worn tools back to new Double sided means you need only one stone - not several grades Keep in your wallet for on job site, in garden or in the woods Ideal for carbide and HSS tools Apply gentle pressure and use with Trend lapping fluid