Frost Cutlery & Knives - 6" x 2" diamond sharpener mounted on a plastic block. Model: FBM6MD. Medium 325 grit. Purple housing. A thin layer of perforated steel is molded into a plastic base. The metal is covered with diamonds of precision size, embedded in nickel. The unique pattern of plastic islands in a "sea of diamonds" speeds sharpening and cleans away fines. Uses only water for lubrication. Hang packaged.