5” square size easy-to-use square protractor, made by 3mm thickness strong plastic, make it a pilot favorite tool. It shows 0-360 scale on outside edge, also shows NW, NE, SE, SW on each corner. This CSP-6 protactor comes with black numbers and blue reciprocal markings for quick and easy measurement. Central grid measured 1:50,000 NM scale for flight planning. An ideal tool for both official pilot and flying school students.