Material: These sanding blocks are made of high-quality brown corundum sandpaper and high-density sponge, acid and alkali resistant, durable and not easy to break. Each sanding block measures approximately 3.94 x 2.76 x 0.98 inches and is easy to hold and use. Wet and Dry Usable: Our sanding sponge block is not only suitable for polishing dry surfaces of objects, but also suitable for wet surfaces, because the sponge has good water absorption, which means it can maintain polishing with water. Washable and Reusable: These sanding blocks are washable and reusable, very convenient to clean after use, you can rinse with water directly. After cleaning and drying, they can be reused. Widely used: The sanding block is suitable for many kinds of surfaces. Such as wood, paint, metal, plastic or walls. You can use them to clean kitchen utensils, polish wooden furniture, remove rust from metal equipment or polish amber surfaces.