1、Excellent Carbon Steel Material: This fastened protractor is made of excellent carbon steel, which is sturdy and wear resistant, not easy to be damaged, and has a long service life. 2、High Accuracy Scale: This fastened protractor adopts high accuracy laser engraved scale, which is clear and wear resistant, and will not fade. 3、Rotatable Design: This fastened protractor features a rotatable straightedge design that makes the ruler more flexible to use. 4、Multifunctional: This fastened protractor can be used to measure angles as well as scribe lines in a variety of functions. 5、Wide Application: This fastened protractor is very widely used, and can be used for crafts, furniture making, woodworking, DIY and so on.