The ruler and protractor set is made of aluminum alloy with high hardness, sturdy and durable, not easy to bend and break, and can be used for a long time.The protractor metal has smooth edges and does not hurt hands. The scale is printed with ink, clear and accurate, not easy to fade. With the hollow design, you can quickly draw the desired shape.Rulers are useful tools for architects, engineers, artists, designers and teachers. Can be used in classroom, office, home, etc., easy to measure and create shapes.