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. Aluminum oxide is a tough synthetic mineral that cuts cleanly and leaves a smooth finish.