iGaging’s EZ Pro 18" 4 in 1 Digital Protractor can help you determine all those important trim carpentry angles in one tool. The device looks like a cross between an oversized bevel gauge and a level. Its built-in digital computer monitors the angle of the swiveling leg once you’ve zeroed it out and as you open it up. The gauge provides readings to one hundredth of a degree throughout its 180° range, and a 14" leg extension helps the leg reach into tight corners at the elbow or stretch out to evaluate broader surfaces.
Obviously, the gauge works like a protractor for estimating inside or outside wall corners or when you need to scribe a precise angle onto a workpiece. But, you can also lay your crown molding on top of the base leg so its flat back is flush, then scissor the tool’s other leg open and rest it against the molding’s angled top edge. The display can show you this top angle or, by toggling with a separate button, you can find the molding’s sprung angle as well. An extensive chart in the manual provides miter saw settings once you know the wall corner angle and the sprung angle. Could be very helpful for the jobsite or to take the mystery out of cutting crown precisely if you don’t install it very often.
In addition to being an angle finder, protractor and digital crown molding device — three of four functions — it also comes with a pair of spirit levels. Seems like a very good value for $59.