OOTDTY Grit #3000 Rectangle Ruby Knife Sharpening Grindstone Whetstone Polishing Stone Oil StoneFeatures: . Ruby sharpening stone is made of sintered synthetic ruby crystals. It is extremely hard, retains its shape well and is resistant to wear. Because they are so hard that they can sharpen and finish extremely hard metals such as carbide engraving, but also work on non-metallic glass, porcelain and quartz. For sharpening and polishing chilled steel, alloy steel and precision parts, etc. These ruby sharpening stones can sharpen and polish triangular sawtooth, circular saw blade, flat blade edge, small serrated mold. The sharpening stone can use oil or water. Specifications:Color: RedSize: 150mm/5.91"× 20mm/0.79"× 5mm/0.20Grit: 3000 #Uwaga:Transition: 1cm=10mm=0.39 inchPlease allow 0-1cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!Package Included:1 Grindstone Sharpening ×