The Norton A275 NorGrip open-coat hook and loop abrasive disc offers excellent durability and value. The NorGrip hook and loop fastener is easy to press on and tear off, and makes disc changes fast. This disc is commonly used for preparing primed and painted surfaces, sanding plastics and fiberglass, and bare wood sanding. Coated abrasives have individual abrasive grains spaced at a predetermined distance from one another. This is an open-coat disc. An open coat covers 50 to 70 percent of the surface with abrasive grains, for greater flexibility and clog resistance than a closed coat, which covers 100 percent of the surface. An open coat allows for longer usage time because it clogs less, while a closed coat offers a finer surface finish than an equivalent open-coat abrasive. High strength, fiber-reinforced B weight (paper is classified from A to F weight, F being the heaviest and least flexible) is strong, which means reduced edge wear during use. This disc is suitable for use with a die grinder or orbital sander. Use with molded-rubber back up pads on a grinder. Use a hard pad for aggressive cutting, a medium pad for general-purpose applications, or a soft pad for contours and fine finishing work. Or, with a random orbital sander, use a foam back up pad to match the application. Foam pads can come in different combinations of shape and density for finer or more aggressive work. For example, use a low profile for uniform contact with the work surface or a tapered edge for small contours or inside corners, soft density for 320 grit and finer sanding, and medium density for grits coarser than 320. The five-inch diameter disc has five vacuum holes, while the six-inch diameter disc has six vacuum holes. Ensure that the holes on the disc are lined up with the holes on the backing pad, in order to properly draw the debris and dust away from the workpiece. Aluminum oxide is a widely used and versatile abrasive material. It is a tough, fracture- and wear-resistant grit that works well with a broad range of materials, from metals to wood. Aluminum oxide is more durable than silicon carbide and often used for material removal and finishing. P-graded abrasive grains are held to a closer tolerance than non-P-graded abrasives, which means that they offer a more consistent surface finish. Abrasives are used for a variety of applications from shaping a part to fine finishing, depending on the grit size. Low grit numbers like 40 are coarse and are used for removing excess material and shaping a part. High grit numbers like 400 are fine and help to create a smooth surface finish. Norton Abrasives manufactures a wide variety of sanding, grinding, and polishing abrasives, and has been located in the United States since 1885. In 1990, Saint-Gobain purchased Norton, keeping its manufacturing facilities and offices in the same location. Norton/Saint-Gobain has been recognized as a Global 100 Sustainable Company, as well as earning ISO 9000 and 14001 certification for quality and environmental management standards.