Learning Advantage Dry Erase Magnetic Protractor Whiteboard Measurement Tool DESIGNED FOR THE CLASSROOM--This oversized large magnetic protractor is perfect for teaching a class when using a whiteboard. It includes magnets which will help position the protractor while drawing, as well as an ergonomic handle to ensure accurate drawings can be made PAIRS WELL--Use in conjunction with our whiteboard compass and magnetic whiteboard straight edge tools to complete the classroom geometry experience BUILT TO LAST--The protractor is made from durable plastic which allows it to handle numerous drops and years of use in the class setting Marked to 10 inches (and 30 cm) along straightedge