VERSATILE: This 4 sided diamond sharpening block has four different grades of diamond for honing and sharpening blades of all types and can be used wet or dry. EASY TO USE: The holding base has non-slip rubberised feet at either end, ensuring a good grip and ease of use. GRADES: Each 150mm x 50mm side has a different grade: red side (fine) , green side (medium) , yellow side (coarse) , grey side (extra course) .