Vintage Keuffel & Esser Co. Paragon Protractor for Drafting, Engineering, Architecture. It was manufactured in the USA. It measures angles from 0 to 180 degrees. It has a vernier gauge for precise measurements and a circular viewing pane with crosshairs for pinpointing a source location.. The base is 7-1/2 inches across and the arm is 10 inches long. It is in really nice condition. The arm moves smoothly over its full range.