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.

Norton 66623325035 - 2" 120 Grit Fine Grade Aluminum Oxide Vortex Rapid Prep Green TR Non-Woven Surface Preparation Disc, 50 Each
Insize 6313-1D8, SETTING RING, 1.8" dia, 6928640357756
3M 19764, Utility Cloth Sheet 314D, 9 in x 11 in P320 J-weight, 7000000352
3M 19795, Utility Cloth Roll 314D, P400 J-weight, 1-1/2 in x 20 yd, 7100081717
3M 20967, Portable Utility Cloth Roll 314D, P240 J-weight, 1 in x 20 yd, 7010290604 
