Review on Enhanced Accuracy and Clarity: Universal Protractor Magnifying Internal Measurement by Josh Parson

Excellent price. Under a magnifying glass with my Starrett protractor, I see a 2 inch difference. I need an everyday protractor that is accurate and affordable as they get a bit abused in the greensand foundry. The packaging oil was a bit thick, better safe than sorry. In addition, the blades twitched slightly when in use. A quick pass of a jeweler's file around the corners and it's smooth. I highly recommend it. It is good enough for both the machine operator and for working with tools and dies.