Corner sanding sponge sands both sides of drywall interior corners at the same time. Creates near-perfecr angles. Resistant: lasts longer than sandpaper. Reusable: rinses clean with water. Versatile: use wet or dry. Fine grit on 3 sides. 2-1/2 in. (64 mm). Note: For use with hand sander #5121000 (sold separately). Can also be used by hand.