3M SandBlaster dust channeling sanding sponges are built for the demands of your job. This unique sponge channels dust away from the sanding surface. They are ideal for sanding painted surfaces and resist loading which allows for larger sanding coverage and faster sanding. Can be used on wood or metal. Use coarse grits to remove coatings， medium grits for bare surface sanding and fine grits for between coats sanding. When compared to 3M conventional sanding sponges.