to create abrasive slurry for effective sharpening with less pressure than an oilstone requiresCombination stone has 3000 grit on one face for maintaining and refining, and 8000 grit on the opposite face for polishing steel cutting edgesCleans up with Water as lubricant instead of oilBlue plastic hinged box with no- can be used as holder for the stone during sharpeningSize: 18 * 6 * 3cmSquare grindstone size: 6 * 3 * 3cmKnife sharpener stone is made by two sided professional grit which are designed to sharpen and polish .Instruction for Use the stone in Water at least 5-10 minutes sharpeningInsert knife into the angle guideHold knife at angle and stroke the blade acrosssideAlternate blade sides each stroke or 2-3 strokesTurn the stone over and polish the blade sideTest the burr with paper, no fingerClean the stone and knife, it in dry placeColor: White + GreenMaterial: White corundumPackage Contents:1 x 2-Sided Knife Sharpening Stone1 x base holder1 x Square grindstoneOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.