This sharpening stone from Westmark combines a 400 grain surface in red and a 1000 grain surface in blue. Use the red surface for ongoing sharpening and the blue surface for initial sharpening. It sits in an anti-slip rubber base. The stone is made from corundum and has an overall length of 18.5cm/7.3in. It is 6.5cm/2.6in wide and 3cm.1.2in deep. The stone comes with a 2 year guarantee from Westmark.