Use the straight side of this double strip ruler to cut 1 1/2" and 2 1/2'' strips – or use the pre-cuts that are on the market. Sew these strips together to create a 4 1/2" wide strip set. Turn-a-Round the ruler to cut 60° triangles that finish 4". Place two strips of fabric – right sides together – and cut 5 pair of half-square triangles at one time without wasting any fabric. The holes in the ruler enable the rotary cutter to cut the triangles without damaging the ruler. Our exclusive embedded gripper dots hold the fabric while cutting when pressure is applied.