This is a BIG idea with poor quality control and no customer support from Starrett. The first one I received was rejected with more than one degree. The second one I have is DEAD ON EXACT! Thanks again to Revain for the excellent customer service. IF you get EXACTLY ONE it will be a great tool. The scale circle is large enough to move the tool away from the bonded drywall corners and is easy to read. As for the first tool, I decided to contact Starrett directly rather than returning it to Revane immediately. I have several of my father's Starrett instruments that are very dear to me. They're all great, and back then, Dad ONLY bought Starrett gauges. UPDATE: I called Starrett and their response was basically that this is a "Chinese hand tool" and therefore falls short of Starrett's expectations for accuracy. CONCLUSION: If you're one of the most people who get a fairly accurate instrument, then this comes in very handy, otherwise it's a good dog chew toy. To be honest I cannot understand why Starrett would allow his company name to be placed on an inconsistently accurate instrument. My father is a machinist turning in his grave. Although that's exactly what I like.