Good Stability: The drawing tool is made of aluminium, not easy to rust, good hardness, high strength, good corrosion resistance and easy to operate High Precision Drawing: The circular tool can be used to draw circular measurements and so on. It is adjustable and can be big or small. Just rotate the ring to open and close its attractive aperture mechanism. The maximum diameter of the circle that can be drawn is about 12.5 cm/4.9 inches Measurement Function Integrated: Not only can it be used for drawing, but it can also be used for measuring at the same time. During the drawing process, it is able to directly measure the radius, diameter and other parameters of the drawn circle for easy checking and modification. Improves ease of work and reduces the hassle of using separate measuring tools Adjustability: The diameter becomes larger with clockwise rotation and smaller with counterclockwise rotation. This is an easy-to-carry plotter and precision measuring instrument for industrial use Lightweight and Effective: Portable and Versatile This plotter is lightweight and easy to carry for professionals, students and artists who need to draw circles on the go or in different environments Colour:As Shown Material:aluminum Package Contents: 1pcs x circle drawing tool