Features: It is a completely redesigned tool for drawing and measuring perfect circles. Made of aluminum alloy and stainless steel material, good corrosion resistance, not easy to . It's perimeter can be enlarged or reduced. It can be used to draw round measurements and so on. This is an easy to carry plotter, and can be used in industry. Simply rotate the rings to open and close its captivating aperture mechanism. Specifications: Type: circle drawing tool Material: aluminum alloy + stainless steel Color: gold, black Size: about 12.5cm Package Include 1pc x circle drawing tool Note: Please allow 0-1 cm error due to manual measurement. please make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. If you use a lag, you can add lubricant oil to it.