Regular Blade Finish; graduations: No. 4R: 1/8", 1/16", Quick Reading, 1/32", 1/64" * Direct reading 0-180 degree in opposite directions, permitting the direct reading of angles and supplementary angles * Protractor heads are made of stable cast iron and finished with a choice of attractive black wrinkle finish; tempered steel blades with accurate, machine-divided graduations * Reversible lock bolt allows choice of which graduated side of the blade faces the operator * A spirit level indicates when the base reference surface is level-a feature not usually available on comparable rotractors