Versatile Rolling RulerEasily draw horizontal and vertical parallel lines. Draw circles up to 28 cm in diameter. Draw angles with the built-in protractor. Draw curves, arcs and other geometric figures.Drawing roller rulerBuilt-in roller, smooth sliding, stable drawing and not easy to tilt. There are parallel scales, various formulas and conversion factors on the drum for easy viewing at any time.Transparent Scale RulerThe printed black scale of the ruler is clear and easy to observe. Marked in metric and inch. The transparent ruler allows you to draw without skipping some important graphics or texts.Material and precautionsMade of impact-resistant plastic, lightweight, easy to carry, practical and durable. Note: This roller ruler is only suitable for use on relatively high friction surfaces such as drawing paper and canvas, and not suitable for use on too smooth surfaces.Widely UsedWhether you are an artist , student, designer or architect, this drawing parallel ruler is a good helper for your work or study. It can help students develop their surveying and mapping skills and spatial imagination to meet different needs. Note: The data are all manual measurement, please allow some error of 1 - 3cm, due to the light and display difference, there will be some color difference, depending on the physical object received.