Ideal for squaring off corners and cutting triangles and squares from 1" to 8". 8" x 8" ruler folds diagonally into a triangle for added versatility. 1/4" seam allowance makes adding seams easy.Clear line intersections enhance visibility. Markings can be read on light, dark and patterned fabrics. Made of 3 mm-thick, premium-quality, clear acrylic for lasting durability.