Koala Ring Ruler 3"-6" Diameter
The Ring Ruler is the first size-adjustable, circular ruler. It has been designed to make the drawing and measuring of circles and arcs a much simpler and more efficient experience by eliminating the cumbersome pivot-point system. Not only is the natural feel of expanding and contracting a circular ruler more ergonomic than using a needle compass, it is also quicker, safer and provides more the useful circular metrics of diameter and circumference (arc length). One of the best features of the Ring Ruler is its simplicity. This makes it a great learning tool for children- especially ones too young to handle a circle compass. Available in US Standard and Metric Scales