I just pulled on older one that I bought a couple of years ago. It is 6.5 by 24. The markings on the ruler are the width of the strip you will cut. When I have the fabric layered for cutting and squared on the left edge I place the cutter marking for the width of the strip I desire on the squared left edge (2.5 mark gives me 2.5 inch strips). The blade will be on the right and the markings take into account what you can't see under the ruler.
Hope that helps. If you need pictures let me know.