Every Quilter's worst nightmare is a rotary blade injury.Birllaid non slip grips be absolute must have for seamstresses and quilters!! If your ruler had been sliding when you cut the fabric,don’t hesitate to buy these non-slip ruler grips. They are clear silicone and do a great job at keeping the ruler stable during cutting fabric. They were easy to put on & really do a great job! There are 72 larger rings, and 72 smaller dots (one inside each ring.) all of these can be used on the back of the ruler. With these true grips,No slipping whatsoever. You can use the large rings on your large ruler, and the smaller bits from inside the rings (the donut holes) on your 60-degree triangular ruler. This will be a small but inexpensive & helpful accessory for your quilt rulers. They are so thin, so they don't add much bulk to the ruler. And they are non-slip, so you can get an accurate cut every time.