The 3M™ Fibre Disc Back-Up Pad is a ribbed, one piece construction with holes, designed for cool running of 3M™ Fibre Discs. The firm pad allows for good breakdown of various minerals, including discs using ceramic minerals, such as 3M™ Cubitron™ Products. Each pad, along with one retainer nut, is conveniently packaged in an easy open box.