Pack of 2 6-Inch Backing Pad 2PCS per pack, 6” PU Hook and Loop Backing Pad, Non-Vacuum Style, 5/16”-24 Threads, 12000 RPM Maximum Operating Speed Great for general-purpose sanding and polishing; suitable for dual action air random orbit sander/polisher with 5/16" diameter shaft, like PORTER-CABLE 7424XP Made of High Quality Polyurethane: durable, lightweight, flexible, heat-resistant and well-balanced Reinforced Inner Construction: utilize steel struts molded into center hub to withstand high frequency while achieving a consistent, smooth finish Hook and loop attachment system make disc change easy and fast; The 29-degree tapered edge offers excellent flexibility