The desired length of the strip can be torn from the roll for a specific application. Most grades have a light, J-weight cloth backing that provides the flexibility needed to conform to circular edges, angles, or other contours. Rolls in grades P50 or P60 have a slightly stiffer X-weight backing suitable for more coarse sanding applications. Cloth remains durable even when bent or rolled, without tearing or shelling, but strips can be torn by hand when a smaller piece is needed, without compromising the sanding surface.
Aluminum oxide is a popular choice among industrial professionals because of its fast cut-rate and long life. This mineral makes a tough, durable abrasive that self-fractures to expose fresh cutting edges, whereas traditional natural abrasives dull more quickly. Aluminum oxide is suitable for a wide variety of materials in both woodworking and metalworking, including ferrous alloys. Aluminum oxide abrasive can be used on ferrous and non-ferrous metals, wood, and plastic.

Standard Abrasives 877002, Unitized Mounted Point, 811 B52 x 1/8 in, 3M 7100025527
3M 86992, Diamond Disc, 3" Roloc, 674W, 120 Mesh, TR, 7100143477, Box of 5
3M 21543, Scotch-Brite Roloc Clean and Strip XT Pro Extra Cut Disc, TR, 2 in x NH, A XCS, 7100179815, 60/box
3M 77792, Textured Surface Applicator TSA-2, For Mortar Joints And inside Corners, 1 Ea/Case, 7000005252
3M 19768, Utility Cloth Sheet 314D, 9 in x 11 in P180 J-weight, 7000000356 
