I couldn't find this in the fabric stores so I was happy to find it on Amazon.  Very easy to put on the rulers and works great.  I was able to hold my large ruler with one hand and cut a 24 inch length of fabric with my rotary cutter.  The only negative is that they sent three rolls of the stuff.  I covered four rulers and didn't even use up just one of the rolls.  I'll have to find some quilting friends and share with them the other rolls.