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.

ACS Diamond Cloth Belt, CX1250 1/4" X 24" 75U
3M 53735, Drywall Sanding Sheets 9091NA, 4.1875 in x 11 in, 2 Sheet Fine Grit, 7010314729
Standard Abrasives 32953, PSA A/O Disc, 711880, 2 in x NH, 60, 7010310798
3M 19768, Utility Cloth Sheet 314D, 9 in x 11 in P180 J-weight, 7000000356
3M 97106, Cartridge Roll 341D, 80 X-weight, 5/8 in x 1-1/2 in x 1/8 in, 7010327460
Standard Abrasives 541152, Quick Change TS P.A.R.T. #30 Disc Mandrel, 5/8 in TA4 (PILOT), 7000121724 
