I love the extra 6" length on this one for when I have large 1/2" scale groundplans to measure, especially when doing the triangulation method. The markings are very clear - no more of that 5 vs 8 screw up that I do so often on the regular size scale rule on overlapping scales. FYI - since this one didn't come with a case I created my own to protect from dings - fits great inside a mailing tube, with some PVC end caps and a few cotton balls to fill up the extra room at the ends.