3M™ Pro-Pak™ Wetordry™ Silicon Carbide Sandpaper for use between coats on paint or varnish. Durable "C" weight backing for maximum sanding. Ideal for sanding/finishing metal, plastic, fiberglass and between coats. 3M™ Pro-Pak™ Wetordry™ sanding sheets can be used with water to reduce clogging and extend abrasive life.