Double-Sided Water Stone Knife Sharpener Sharpening Dual Whetstone (3000/8000) Special proportioned white corundum made waterstone, high hardness and wearproof. Fine texture and sharpening force ensure sharpening speed. Double-sided water stone.Small number side for grit coarse sharpening and Large number side for grit fine sharpening. Good choice for kitchen knife, outdoor knife,precision tool, sushi knife straight razor and so on. Don't Scrape off the starch solution, it will help sharping the knife. Two size give you a alternative choice coordinate to different situations.