This tool was designed to measure from the center, making extremely accurate 4-triangle squares. Start by first cutting the triangles larger than they need to be, then stitch the triangles to make a square. Just center the trimmer on the sewn unit and trim the edges to the perfect size for the perfect quilt every time! Makes perfect 1 1/2 (2 1/2, 3 1/2, 4 1/2, 5 1/2, 6 1/2)" squares. Made in the USA.