This revolutionary, patented sanding material is made like an open screen with thousands of holes for longer life and less clogging than normal abrasives. Use a 2" hook and loop type holder to hold the discs. They will cut fast, and stay cooler than standard sanding discs. They can be used for wet or dry sanding and can be washed out after use. Using an innerface backing pad to protect the holder is recommended.The Kit includes two discs of 80,120, 180, 240, 320, and 400 grits.