Agile-shop Double Side Diamond Ceramic Knife Sharpening Stone Whetstone DMD 400/1000# Dual Side: #400 #1000 Size: 28*5.5*2cm (Length*Width*Height) Much more efficiency than waterstones and Less risk of damaging the edges Do not use the knife sharpener to sharpen serrated blades. Do not put the sharpener in the dishwasher or submerge in water