Omnigrip 20.5in Non-Slip Square Quilter's Ruler is made especially for quilting, sewing and crafting projects to cut strips and square up finished quilt blocks. There's a diagonal line for triangle cuts and the ruler can be used with rotary cutters or straight edge blades. Features a clear background and neon lines with a highlighted edge for trimming and clear angle markings. The ruler has extra 1/2in on two sides for seam allowance. Ruler measures: 20.5in x 20.5in