This innovative 3-in-1 ruler and compass makes it easy to draw precise circles up to 12" in diameter! For larger circles, simply place pen or pencil in the appropriate hole (1/8" increments), hold the center disk, and sweep the ruler around it's center point. Smaller circles, from 1/16" to 9/16" diameter, are easily drawn with the integrated circle templates into the ruler body. And along the outer edge of the ruler are 12" & 30cm graduations perfect for measuring! Unique product is much easier for young children to manipulate and use than a standard compass, and the integrated design means that they can more easily understand how angles and measurements correspond with each other. The perfect tool for young students working on mastering geometry and angles!