The Faithfull Curved Diamond Whetstone is a uniquely shaped stone specially designed for the sharpening of wood turning tools and carving chisels. Its curved diamond surface lets you sharpen both concave and convex surfaces. The small end has a radius of approx. 3mm (1/8in) and tapers up to the large end with a radius of 28mm (1.1/8in). The double sided steel stone is coated with mono crystalline diamond in 600G medium and 1200G fine grits. The 600G grit is for sharpening blunt edges and the 1200G grit is for final honing of the edge. Can be used dry or with water as a lubricant, no oils are necessary. Specification: Size: 250 x 56 x 17mmAdditional Information:Whetstone Type: CurvedGrit Type: Medium/FineLength (mm): 250