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 " 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" thick, optically clear acrylic to eliminate parallax and allow close pencil tolerance. Available with or without inking edge.