The Ace sanding sheets are made with silicon carbide to really dig-in to a fine finish while resisting breakdown and loading up when wet sanding. The premium backing allows the sandpaper to be submerged in water for an extended period of time without any adverse effects on the quality of the sanding sheet. Features: For wet sanding primers, base coats, and top coats For hand or machine sanding Material: Silicon Carbide Grit type: Assorted Size: 28 cm (length) x 23 cm (width) Number in package: 4