I use sandpaper disks. I used to use the clear stuff that adheres to the ruler, but found that it was almost as slippery as without, so my friend talked me into using the disks and I don't have nearly the problems with the ruler slipping. It did take some getting use to because the ruler doesn't just slid along, you have to pick it up slightly to move it, but once you get used to it, you will love it.