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.

Dynabrade 78128 3" Dia. Coarse NWN VT DynaBrite Locking-Type Disc, 25/pack
3M 22409, Roloc Disc 361F, P120 XF-weight, TR, 1-1/2 in, Die R150S, 7000045103
Standard Abrasives 727395, Buff and Blend Cross Buff HS, A/O Coarse, 2 in x 1/2 in x 2 Ply x 8-32, 7010299537
3M 45714, Cubitron II Hookit Cloth Disc 947A, 120+ X-weight, 3 in x NH, D/F 3HL, Die 300BE, 7100113113
Dynabrade 90875 2" Dia. Super Fine NWN DynaBrite Locking-Type Disc, 25/pack
3M 19764, Utility Cloth Sheet 314D, 9 in x 11 in P320 J-weight, 7000000352 
