W10 Double sided (combination) diamond whetstones will not break, chip, crack, hollow or groove. These ultra precision whetstones are lightweight and have a totally rigid construction. Use water for lubrication no oil, smell or mess and can hone ALL hard materials carbide, steel, the grits are denoted by a dual coloured circle which is set into one end. Black Extra Coarse Grade 220, 60 micron Blue Coarse Grade 325, 45 micron Red Fine Grade 600, 25 micron Green Extra Fine Grade 1200, 9 micron The Blue side is suitable for general carpentry tools, tinsnips, side cutters, wood bits, garden tools etc. The Black is suitable for damaged woodworking tools, cold chisels, axes, lawn edgers etc. Black Extra Coarse 220g, 60 micron Blue Coarse 325g, 45 micron