This TWIN Pro 250/1000 Combination Japanese Water Stone has two sides, a coarse 250 grit stone for especially dull knives or reshaping blades, and a fine 1000 grit stone for the finishing touches. The base has non-slip rubber feet so you can safely sharpen your knives on most surfaces. Having sharp knives in the kitchen is a great advantage. With this sharpening stone, you can sharpen blunt blades yourself. It is specially designed for ZWILLING blades to give absolute sharpness. It measures approximately 20cm x 8.5cm x 4cm.