I used this product for a pair of inserts on a quilt - making 2" squares - it is a time saver, and does make your seams line up correctly. The inserts were about 40" x 10" finished. A technique you need to use - sew one line from the top, the next from the bottom, so that the continual use of one direction does not distort the finished project. ALSO -- the brand we used left red dye marks on our machines -- so they need to be covered with a protective layer of clear plastic attached with tape to minimize this problem.