Crystal clear acrylic with a white protractor arc and beveled inking edge. Built-in magnifier allows for exact settings. Thumbscrew knob locks angle in place. Combines functions of a triangle and protractor. Has three sets of graduations: degree, slope, and rise. Use as a drafting square when opened up to 90 degrees. Easily find trigonometric functions using included instructions. Measures approximately 6 1/2 x 8 x 9 1/4 inch and 0.125 inch thick.