3M Pro Grade Precision Ultra Flexible Sanding Sheets feature an innovative film backing so you can FOLD, ROLL or SHAPE into any form you need to get the job done. The tough backing resists puncture, tear and creases, helping the sheet keep its original shape. Tough film backing can be used for wet or dry sanding. 100 grit (Medium) ultra flexible sanding sheets for smoothing stage. Use with 3M pro grade precision large sanding tool for more traction and consistent sanding. For the best results, sand with the grain of the surface and work through a sequence of grits, from coarse to very fine, skipping no more than 1 grit step between each sanding step (other grits not included - sheets are sold in 100, 150, 220 and 320 grit). Perfect for sanding flat surfaces.