Estone 10000 3000 Grit Knife Razor Sharpener Stone Whetstone Polishing Tool Two Sides A fine-grained whetstone lubricated with oil, used for fine sharpening The Ruby sharpening stone and Agate Stone, For Polishing, Sharpening Can make mirror surface, mirror finish The Ruby Sharpening stone is made from sintered crystals of synthetic ruby It's extremely hard, maintain their shape well and are resistant to wear