Provides the features of a 45/90 adjustable triangle plus those of a protractor, Angles from 0 to 90 can be drawn from the baseline with 1/2 inch accuracy, Die-engraved graduations for high visibility, The aluminum thumbscrew securely holds the selected angle and allows quick pickup and manipulation, Made of high impact, 0, 100 inch thick, optically clear acrylic to eliminate parallax and allow close pencil tolerance, SKU: ALV7438