Ring Ruler Size:Standard ( 3" - 6.5" Diameter ) ** By connecting straight edges

** By connecting straight edges to create a track

And here are the catalog-friendly bullet-point features:

This isn't your typical kindergartener's beginner pencil

accurately

Ring Ruler Size:Standard ( 3" - 6.5" Diameter ) ** By connecting straight edgesThe 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