The Omnigrid marking ruler trio contains 3 rulers that can be used to quickly and accurately perform a variety of marking tasks when quilting; their center lines are exactly ¼ from both edges of the rulers, providing an excellent reference line for marking ¼ sewing lines, adding and checking 1/4 seam allowances and marking ¼ quilting lines.  Three convenient lengths: 4", 6" and 12".  Use a pencil with a fine, sharp point for the most accurate mark.  Do not use with rotary cutters, knives or other cutting instruments.  Rulers are designed for marking use only.