An educational compass with a centre wheel and extension bar.
A drawing compass (or drafting compass) is an instrument used in technical drawing to draw circles, semi-circles or arcs. They can also be used to measure distance on maps, and in mathematics. They are used extensively in teaching, and non-digital drafting and are an essential tool for the art enthusiast, draftsman or learner.
Made of metal or plastic, a compass has two parts (legs), one has a spike on to be used as a central point, and the other has a pencil lead, pen or holder to do the drawing. They vary quite a lot in quality and design depending on the intended use.