This multi-sized ruler features easy to read black and white markings. The math required to cut these angles is incorporated into these markings. Use the 45° side to cut half-square triangles from fabric strips up to 5 1/2 wide. Create half-square triangles that finish up to 5. Turn it around to cut 90° triangles that finish up to 5. Our exclusive embedded gripper dots hold the fabric while cutting when pressure is applied.