Alumicolor™ offers Compass Rules in 12" and 18" sizes. Compass Rule sets include the shaft, anchor point, lead holder and lead all in one package. Make circles up to 24" with the 12" set or 36" with the 18" set.
Automatically gives radius, area and circumference. Adjust circle size with fingertip control. Calibrations in inches on one side and metric on the other.