The Edge Master Professional Combination Whetstone with 400/1000 Grit allows you to repair dull knives and restore their sharpness. Soak this ceramic whetstone for 5 minutes then swipe the knife edge at a consistent angle. It includes a plastic base to keep the stone steady while in use. Includes two kinds of whetstones to repair chipped edges (coarse 400 grit) and resharpen dull knives and remove burrs (medium 1000 grit) Needs to be submerged in water for about 5 minutes (or until bubbles are no longer present) before use Ideal for sharpening straight-edge knives at a 15 to 30-degree angle through a constant back-and-forth motion Comes with a non-slip base to keep the whetstone in place while sharpening Construction: Ceramic and plastic Dimensions: 18.5cm x 6cm x 3.25cm Cleaning and care: Rinse with water then leave to dry in a well-ventilated area