I love Quilter's Select rulers. They are so easy to read and non slip. You can make any ruler non slip by spraying a no slip coating on the back. It's fantastic for all the older rulers. I have a lot of Missouri Star rulers and templates and this stuff is wonderful. It's great for machine quilting rulers too. No extra thickness on the ruler.
Odif Non Slip Coating. It dries in about a minute. Lint and thread will wipe off. Also get the Odif Glue Cleaner spray. It takes the sticky off scissors, rulers, etc. I always have these two products in my sewing room.