Alumicolor 18" Beam Compass Rule solves the problem of making perfect large circles up to 36" in diameter. This beam compass attaches to thin profile yardsticks and automatically shows figures for the radius, circumference, and area of any circle in inches or centimeters.

Solves the problem of making perfect large circles up to 36" in diameter. This beam compass attaches to thin profile yardsticks and automatically shows figures for the radius circumference and area of any circle in inches or centimeters.