The prep stone is used with the finest grits of the Norton waterstones. The prep stone creates a slurry that helps polish the edge of the knife or tool. The stone is made of aluminum oxide abrasive. The stone measures 3/4" x 3/4" x 3" in length.
For final polish, use this stone by rubbing it against the face of your 8000 grit waterstone. This process slightly flattens the stone and prepares it for the final step in the sharpening process.
Norton Part Number: 66243439361