I was having difficulty sanding back spotted gum screens with regular 40 grit paper as the paper was wearing out too quickly and not particularly effective. I bought these hoping for an improvement and they are. Much more effective at removing the existing finish and they last at least 2 or 3 times longer. A couple of comments: 1. it’s much easier to score the surface with the same amount of pressure as regular paper so a much lighter touch is required. 2. The velcro doesn’t seem as sticky as other brands, so it often shifts around on the sanding back and I did have a couple of occasions when the sanding disc flew off. I use a metabo sander in case that makes the difference. I am happy to have found them as they make a truly awful job somewhat easier. Was shipped quickly.