The Precision Trimmer 3 Ruler by Marsha McCloskey of Feathered Star Products.
This ruler was designed to measure from the center. Make extremely accurate 4-triangles squares by first cutting the triangles larger than they need to be, then stitching the triangles to make a square. Center the Precision Trimmer 3 on the sewn unit and trim the edges to the perfect size.
This ruler is suggested for use in our Raspberry and Cream Block of the Month program.