R&H Mangrove Yellow-Foam Professional Dual Action Random Orbital Sanding Velcro Backing Plate 150mm with 10mm PU Thickness. 6" x5/16" x24 Thread. No Holes.

5 inch hook and loop replacement pad features 6 holes, fits most sanding discs, 5/16"-24 thread
Velcro pads are lightweight and perfectly balanced for faster work and a professional finish
Quick and easy disc change with micro hook and loop attachment system
A high quality backing plate with 6 hole vacuum pattern, ideal for use with dust free sandpaper discs with a diameter of 5 inches.
The strong center core of the plate is reinforced with steel struts to keep it well balanced and stable when in use, and you apply even pressure.