The Norton three-piece back-up pad conversion kit includes one air-cooled rubber back-up pad and two medium-grit aluminum oxide fiber discs for general grinding applications. Applying the back-up pad to a right-angle grinder allows fiber discs to be mounted for medium to heavy grinding applications. The slotted hub design of the back-up pad draws cool air behind the disc. Curved ribs on the rubber face force heat away from the disc and back-up pad, which cools the cutting action, reduces disc loading, and increases grinding life. The back-up pad has a 5/8"-11 threaded female hub for mounting. The two aluminum oxide fiber discs included in the kit have a medium grit (50 grit) and suitable for general applications, such as paint stripping, light deburring and finishing, weld grinding, and heavy metal removal. Back-up pads provide the backing surface for attaching a sanding disc to grinders, orbital sanders, polish sanders, and other grinding machines. The back-up pad composition and design affect results. For example, a firm pad provides a more aggressive cut. A medium back-up pad provides greater flexibility. A slotted hub draws cool air behind the disc to reduce generated heat on the workpiece. Sanding discs attach to the back-up pad in a variety of ways, such as with locking nuts, adhesive, or a hook-and-loop system for quick disc changes that don’t require tools. Norton Abrasives manufactures sanding, grinding, and polishing abrasives. The company, founded in 1885, meets International Organization for Standardization (ISO) standards 9000 and 14001 for quality and environmental management. What’s in the Box?Back-up padAbrasive discs (quantity: 2)