Review on Precision Measuring Tool: General Tools 1702 Stainless Protractor - Accurate Angle Measurement Made Easy! by Joe Glass

For some things it is very convenient that it is 0-180 degrees instead of 0-90-0 degrees is a bit awkward although you also have to keep tightening the lock nut. The resolution is 0.1 degrees, but is actually only accurate to 0.5 degrees. If you only use it for carpentry work or something like that, it's perfect.