The super-sharp abrasive and new coating method make these sponges resist clogging, cut faster and last longer than general sanding sponges and up to 5X longer than conventional sandpaper. The various sizes and grit combinations offer maximum versatility and flexibility for sanding curved, contoured or flat surfaces of wood, metal, paint, plastic, and drywall. Ideal for sanding in long, narrow areas such as between flat chair spindles. Coated 4 sides.