3M 99404 Pro-Pak Aluminum Oxide Sandpaper, 9" x 11", Medium 100 Grit, 25-Count3M Aluminum Oxide Sandpaper for use on Wood, Metals, Paints, Plastics and Fiberglass. For Hand or Machine Sanding of Many Different Materials. Open coat resists loading on soft materials. For non critical, short term application. 25 Count Size: 9" x 11" Grade: 100 Converted Form: Sheet Abrasive Mineral Type: Aluminum Oxide Dry sanding only on machine or by hand For non critical, short term application Open coat resists loading on soft materials.