The 3m Pro-Grade Sanding Sponge Is Designed To Provide Great Coverage While Sanding Walls, Wood And More, Has A Sharp Abrasive Mineral For A Fast Cut. Use Wet Or Dry. Sands Flat And Contoured Surfaces. They Are Made From Durable, Flexible Foam And Are Clog-Resistant For Long Life. The Sponge Is Comfortable To Grip And Maintains Its Shape Through A Variety Of Sanding Jobs.