Kuelox Rolling Ruler 
Brand: Kuelox
 Length: 15cm , 20cm, 30cm
 Material: Usually made of transparent plastic, durable and easy to observe when drawing. 
Uses:
 Rolling mechanism : The ruler is equipped with a roller in the middle, allowing smooth movement on the paper surface, making it easy to draw parallel lines without much adjustment.
 Draw parallel lines easily: The roller ruler is equipped with a roller shaft, allowing smooth movement on the paper surface, helping to draw parallel lines quickly and accurately.
 Multi-function combination: Many models of rolling rulers integrate a protractor, compass and positioning holes, allowing for drawing angles, circles and complex geometries.
 Convenient for students: The rolling ruler helps students develop their hand drawing skills and creativity in designing different drawings. 
Details: This is a set of French curve rulers , often used in engineering design, industrial arts, architecture, fashion design, and other fields that require drawing smooth and precise curves that cannot be done with a compass or bare hands.