Sanding pads with velcro come in several sizes. These are 50 mm (2 inch) and 75 mm (3 inch). Everything with a Velcro backing sticks to it. The axis of the sanding pad is 6 mm and therefore fits in the pro sander. But they are also particularly suitable for use in a drilling machine. They are made of a flexible rubber and to last a very long time and they adapt to the shape that you are sanding.
You can brush, polish and sand with it. Be careful not to let the discs get too hot. The hairs of the Velcro can then deform, which reduces the adhesive power. You can find sandpaper for the sanding pads here. 75 mm en 50 mm.