This 20½'' square features easy-to-read black and white markings printed in 1" grids marked in " and ¼'' increments. Use the easy-to-read, numerical black numbers (printed on white dots) and the ¼'' grip sides to cut whole inches. These ¼'' grip sides accentuate the dashed lines printed ¼'' away from two adjoining edges to aid in trimming seam allowances. Use the patented Turn-A-Round feature – designated by the easy to read, numerical white numbers (printed on black dots) and the ½'' grip sides – to add the ½'' seam allowance. Our exclusive gripper holds the fabric while cutting when pressure is applied. A 45° angle is printed in black. White horizontal and vertical lines are printed on the square so the center of the ruler is easily distinguishable.