Protractor is constructed of sturdy stainless steel; unlike plastic protractors, a stainless steel one is the last one you will buy Measuring tool has a 6" adjustable protractor arm that can be held in place with the knurled locking nut; quickly and easily identify angles Angle measure has permanently etched graduations for 0 to 180 degrees in opposite directions Tool measures 3-3/8" long with a 2" square head; perfect for school, commerical or home in machinist, woodworking and homework applications Used the tool for setting bevels and measuring and marking angles, Weight: 0.14 pounds, Manufacturer: General Tools