HSK-A-80x130 (#496962). Even when almost all the sanding on a job is done by machine there is a certain percentage that needs to be done by hand. The problem with that of course is that your average sanding block requires regular sandpaper which you have to cut up to fit the block. And it means stocking a whole set of sheets of sandpaper which, except for the occasional hand sanding, isn't needed much these days. The solution are these sanding blocks which are hook and loop and use either the same 6" diameter sanding disks you use on all the festool sanders or the rectangular 80 x 133 mm sheets used on the LS130 and the RTS 400 Festool sanders. The hook and look means that the sandpaper is easy to attach and remove and the ergonomic shape of the sanding blocks will reduce sanding fatigue. There are three different sanding blocks: The 6" diameter block comes in either a hard pad for rough sanding or a soft pad for finish sanding. The 80 x 133mm block is typically used for edge work and corners. The set of all three comes packed in a mini-systainer. Sanding disks are not included.