with Rise & Slope Smooth edges and clear acrylic The protractor section has a graduation of 1/2 degree between 0 and 90 degrees. 6" (15.2 cm) in size Maximum stiffness and resistance to warping are provided by 3 mm thick clear acrylic. Magnifier enables accurate, readable settings The angle of an adjustable arm can be adjusted from 0 to 90 degrees. Protractor with increments of half a degree Straight edge beveled Designed in the USA