Westcott 6"/15cm Protractor Ruler 180° protractor ruler has 8ths graph, 16ths to the inch and centimeter scales. It is laminated for durability and features a translucent color to allow for viewing through to the page. Westcott Drafting & Drawing Tools are some of the finest products of their kind for students and professionals. Our commitment to meticulous quality and cutting edge innovation in measurement and art materials has earned an unparalleled reputation.