Omnigrid's square rulers are used for secondary cutting of strips and to square up finished quilt blocks. You'll find Omnigrid rulers ranging from 2-1/2" square to 15" square. Many of the square rulers also feature a section of 1/8" grid. They are made of heavy-duty, durable acrylic material and feature a left- and right-hand numbering and angle system. There are patented double-sight lines that show up on light and dark fabrics, so cutting is a breeze.