Twice the sharpening potential of a double sided stone. Each side is coated in a different grade of diamond grit. Sharpening is always easier and more efficient when done progressively. With this four sided stone you only need turn the face through 90° to begin the next stage to achieving a sharp edge. This is perfect for sharpening tools and many household implements. Easy and fast to use with 200, 300, 400 and 600 grit colour coded faces. No oil required just use water to lubricate. Includes non-slip base and storage case. Each diamond surface measures 50mm (2") x 150mm (6").