3M™ Wetordry™ paper disc 431Q features extra fast cutting silicon carbide on a strong, waterproof paper backing that gives you superior finishing for both wet and dry applications on a variety of substrates. Used with water, our 3M™ Wetordry™ discs enable you to rinse areas of the workpiece and the sheet during use to prevent dust and debris from clogging the points of the abrasive and reduce air borne dust, while producing a faster cut at the same time. These versatile discs are ideal on surfaces that tend to generate a lot of dust, such as paint, primer and wood and can also be used dry for finishing metal and gel coats. The adhesive backing provides easy attachment to a random orbital sander. We chose silicon carbide, a mineral that is very hard and fractures easily, resulting in freshly exposed sharp edges that cut extra fast and produce a smooth, professional-looking finish. Silicon carbide products are commonly used for low pressure applications such as paint prep and finishing on wood and metal. While it wears faster than aluminum oxide, it produces a superior finish. 3M™ Wetordry™ products are backed with a 3M™ proprietary durable waterproof paper backing that supports both wet and dry applications. Lighter weight than cloth and smooth rather than textured, paper backing is preferable for lighter applications such as finishing and paint prep. At the same time, many such applications produce a significant amount of dust, clogging the abrasive points and creating an inferior work environment. These effects can be minimized by sanding with water to rinse dust away from the workpiece and the abrasive surface. Wetordry™ 7000120331, Closed Coated PSA, 8 in Diameter Disc, 400 Grit, Super Fine Grade, Silicon Carbide Abrasive, Paper Backing, C-Weight Backing Weight