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.

3M 40208, Cloth Spiral Band 341D, P120 X-weight, 1 in x 1 in, 7100138144
3M 87501, Diamond Grade DG3 Reflective Sheeting 4090DS White for DigitalPrinting, 48 in x 50 yd, 7100088230
Dynabrade 11684 Dynabelter Contact Arm Assembly 4" DIA X 5/8" W., 40 Duro Serrated
3M 19771, Utility Cloth Sheet 314D, 9 in x 11 in P100 J-weight, 7000021272 
