In my opinion, the ideal solution for the measurer's arsenal. There is a button for resetting the angle, i. E. you can measure other angles, relative to the established one. It does not turn on automatically when moving apart, which in my opinion is more of a plus. Smart caliper has already planted 2 batteries just lying in the box, turning on from vibration. Steel rulers can be used both as the arms of the protractor and as the actual ruler. Compared to aluminum, it is more compact. A length of 500 mm is quite sufficient to determine the curvature of the corner. Well, except that it could be a case;) well, this is already more a whim. Great tool. I recommend.