The grid rulers with a wide color line around the edge of the ruler is difficult to line up with edge of the fabric.
Creative Grid rulers have an extra 1/2 " on 2 adjacent sides making it easy to cut the extra 1/2" to have finished sizes of the whole inches, ie. 6 1/2" cut = 6" finished. Creative grid has non-slip on the back. It also has a 8 1/2" wide by 241/2" and 12 1/2". There's an extra large 21 1/2" square. On the web site there's many sizes no normally carried in LQS's.