The Ruby Sharpening stone is Light, portable, and Anti-friction It's extremely hard, maintain their shape well and are resistant to wear Install easy in the a tool or machine, also easy sharpening and polishing all kinds of exact knives For sharpening and polishing chilled steel, alloy steel and precision parts etc Sharpening stone can use oil or water Stone Size: 15 x 2 x 0.5cm / 5.9in x 0.8in x 0.2in(L x W x H) Grit: 3000 Color: ruby Quantity: 10 piece Material: Ruby Whetstone Package Contents: 10 x Ruby Whetstone for Polishing Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.