Thick, Solid and Large Whetstone: Made of professional grade white corundum, perfect for the larger chef's knives, gives a nice working area for any size of knife, -, heat-, edges and corners are clearly demarcated 2 Grit Sides Best Sharpening: 400 grit side has good metal removal rate, light scratches edge. Intermediate stage before finer grits. 1000 grit side leaves metal edge with frosted appearance. Edge sharpness equivalent to majority of factory edges on knives, tools. Suitable for Most Grinding Operations: Kitchen knives, hunting knives, kitchen shears, pocket knife, chef knife, porting knives, straight , cutting class knife grinding, precision tool, garden tools, art appliance and ceramic knife, but serrated and ceramic knife etc Safety with Silicone Mat: The non-slip silicone base keeps the stone firmly in place, amazing experience without moving at all 1000 Grit Side: This grit is a very good overall grit. It is fine enough for many jobs and still have enough abrasive properties to do sharpen knives and tools that are not very dull. If you keep your knives and tools in good shape, you'll find yourself reaching for this grit level often. This grit is also very common for the final stage for many kitchen knives. 400 Grit Side: This fine grit is to put an edge on a tool or knife that exceeds any commercial edge you'll find. This grit is and sharpen very slowly. This is to be used after you've created an edge with more coarse grits. Instructions to use: 1. Soak the sharpening stone with Water for 5 minutes, then put it on a steady such as a table or a desk. 2. First use the 1000 grit side for coarse grinding in 10-30 degree angle, push out with a little force, and then gently retracted. This process takes about 15 minutes. Then use the 4000 grit side for fine grinding. This process takes about 10 minutes. 4. After sharpening , clean with wet cloth or Water, then dry it.<b