Farm Quilter, I have the ruler that is 6 X 12 inches. It is the newer one. The older one was bigger square but no more advantage than the smaller one. The smaller one has a four inch square in the corner that you can measure your squares by. The larger one is the original and I think that is the one they demo on the dvd and in the book. I don't believe they have put out a new book since the smaller one came out.
Happy quilting, Rose