The Blade Tech Whetstone 240 (coarse) & 1000 (extra fine) Grit is an excellent quality stone offering two different sharpening surfaces. The 240 grit is best used for reshaping dull blades. The 1000 grit surface is used to apply a final cutting edge to the blade with amazing results. The stones are best used by submerging them in a bath of water for 5 minutes prior to sharpening.This offers the sharpening surface the best possible lubrication during sharpening. All of the Blade Tech Whetstones are supplied with a rubberised non slip base for secure and easy sharpening. Sharpening surface 18 x 6 cm.