The 3M™ Back-Up Pad is a ribbed, one piece construction with holes. It is 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. Strong Backing for Tough jobs 3M™ Hook and Loop Disc Pad Holders have a center hole with internal threads—choose the thread size that matches the external thread size of your right angle grinder. T-shaped hooks securely hold a surface conditioning disc and provide quick and easy disc attachment, removal, and re-attachment. The hook-and-loop feature enables the disc to be used and re-used for the extent of the abrasive life. Discs are sold separately. Secure and Easy to Switch Our hook-and-loop feature makes disc attachment, removal, and re-attachment easy and facilitates use and re-use of the disc for the extent of the abrasive life. Our disc pads have T-shaped hooks of the type most commonly used in hook-and-loop applications. These disc pads grip the loop backings of hook-and-loop discs and provide a finer finish than do adhesive backed discs. Hook-and-loop systems are designed for work spaces where adhesive backed discs may become contaminated by dust, dirt, or flying debris. Made for Scotch-Brite™ Scotch-Brite™ surface conditioning discs and light grinding/blending products (sold separately) deburr, clean, blend, and finish a wide variety of materials. Using surface conditioning products with a 3M disc pad holder generates finishes suitable for paint.