Forget about using a needle compass—place the power of Pi into your hands with this adjustable ring ruler!

Koala Ring Ruler is a circular ruler that gives you a new and intuitive way to create and measure circular shapes. It provides a useful circular measurement of diameter and circumference (arc length).

The Ring Ruler is very easy to use: simply expand or contract into the desired diameter and quickly snap into place! Quicker and safer than a needle compass, it transforms the process of drawing and measuring circles into an easily traceable, circular motion.

Specifications:

• Available in US Standard and Metric Scales
• Size: Up to 6" (15cm) in Diameter
• Displays diameter and arc length
• Strong flexible plastic construction
• Easy to use
• Rule circles on flat surfaces and on 3D spherical and cylindrical objects