3M Extra Large Angled Drywall Sanding Sponge 910 DSA, 3 5/16 in x 9 in x 1 in 24 cs Fine, Open Stock. 3M Sanding Sponges are designed for wet or dry sanding on drywall. Use this fine grit sponge for smoothing patch and repair on walls. This sponge features conventional 3M abrasives and is made with durable, flexible foam. Sanding is an integral step in preparing a surface to receive a coating. For the best sanding 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 between each sanding step. 3M sanding sponges are available in medium, fine and extra fine grits. Sponge material allows abrasive mineral to form into corner, eliminating gouging. Durable, abrasive mineral coating lasts longer than regular sandpaper.