8 PCS of 3 Inch BACKING PAD? Fits Any Other Sanders That Require A 3 Inch Backing Pad With A 5/16"-24 Thread. Max Operating Speed: 20000 RPM HOOK & LOOP: Each backing pad has a hook & loop fastener for easy application and removal of the device. With this hook-and-loop pad, you can use your sanding tool with confidence in the grip strength of this back attachment. EASY INSTALLATION: Easy screw on installation, attached easily and hassle-free, prevent damage to disc holder. SAVE YOUR TIME AND MONEY: High quality polyurethane material, achieve consistent and smooth finish work, must-have tools for flexible and portable home use. WIDE APPLICATIONS: Suitable for grinding, descaling and polishing ships, metallurgy, automobiles, artificial marble, furniture and wood products.