Annengjin&reg; TAIDEA 240 Grit 7-Inch Professional Knife Sharpening Stone / Single-Side Corundum Whetstone 1.High-grade corundum ensures effective sharpening results. 2.Equipped with a silica gel non-slip base for safety sharpening. 3. 7" x 2.4" x 0.55" ( 180*60*14 mm). 4. Widely used in various knives and tools including kitchen knife, pocket knife, etc. 5. CANNOT be used for ceramic knife, scissors and serrated knife.