Square Ruler Value PackThe Omnigrid square value pack contains Omnigrid quilting rulers; each has an extra 1 2" for seam allowances and diagonal angle lines; use them to cut, square and trim blocks. Diagonal angle line and edge markings for accurate measuring Heavy duty durable acrylic material with laser cut edges for smooth, deep cutting Diagonal angle Patented double sight lines that show up on light and dark fabrics Left and right hand numbering and angle system