The 4 in 1 Multifunction Protractor Angles Measuring Ruler combines precisely measurement with adjustable circular drawing ruler, great for architects, artists, and scrapbooking craft enthusiasts Suitable for students, engineers, and creative professional requiring professional measuring instruments for technical drawings and artistic designs Engineered with construction, this multifunctional protractor geometry drawing ruler measuring tool maintains calibration integrity through repeated use in demanding academic and professional environment Features double angles measurement / circular drawing functions, this Multifunctional geometry drafting tool simplifies complex geometric tasks Optimize efficiency in classroom,, home or workshops with this portable geometry drawing tool that replaces multiple drafting instruments