Norton's Oversized, Extra Firm Sponge For Easier Sanding Of The Entire Drywall Joint Surface. Large Size Is Easy To Hold. Coated 4-Sides. Durable, Abrasive Coated Foam For Lasts Up To 5x Longer Than Sandpaper. Washable For Long Life, Rinse And Reuse. Designed For Sanding Drywall And Gypsum Board.