The stone leveling kit is a 12” diameter, ¼” thick piece of glass, w/ rubber molding installed around the circumference. It comes with a ½ pound bag of 60 grit (coarse) silicon carbide. Use the stone leveling kit to resurface your sharpening stones after heavy use. By sprinkling about a ½ teaspoon of the silicon carbide on the stone leveling kit, and adding a little water, you can grind the high spots of the stone down until it is level again. Use the opposite side as a perfect surface for mounting your Professional or Apex model. The rubber guard will help contain metal shavings and deaden the sound created from leveling stones.