This ruler has been designed to make cutting 2½" wide Jelly Roll Strips quick and easy. The ruler is 16¼ inches long by 5" wide (including triangles), the ruler side is 2½"wide so that you can cut 2½" wide strips as well as triangles. Then Turn-a-Round™ the ruler and line up all the triangles along your strip of fabric and cut multiple triangles all at once. The triangles have the top cut off and will make a 4" finished Quarter Square Triangles QST. Put two strips of fabric together and cut 10 pairs of triangles at the same time. The unique NON-SLIP grip keeps the ruler in place to ensure accuracy. The holes cut out of the ruler enable the rotary cutter to cut past the strip without damaging the ruler.