3M Drywall Sheets are designed for sanding drywall joints, patching compounds and plaster. Made with sharp synthetic mineral for long-lasting performance. Pre-cut 4-3/16 in x 11-1/4 in and die-cut to fit most drywall sanding tools.3M Drywall sanding sheets are designed for sanding drywall joint compounds (light or regular), patching compounds, and plaster. It is made with aluminum oxide, a tough synthetic mineral that cuts cleanly and leaves a smooth finish.