This 60 Degree 12-1/2" Triangle Ruler by Creative Grids provides everything you need to easily and accurately cut triangles! Cut 30 and 60 degree angles up to a finished height of 12 inches. A 1/4" dashed line is printed on each side of the center vertical line so you can cut 30 degree triangles that include the seam allowance. The ruler slides over fabric until pressure is applied. Then, its grip feature holds the fabric in place while cutting, eliminating slipping and miscuts.