The Original True Angle tool is the world's fastest and easiest angle making tool available. Just rotate the blades and read the dial. The hairline locates the exact angle within a tolerance of 5/1000ths of an inch. The blades rotate 360° in both directions. To lock the blades, lightly tighten the finger nut. To unlock the blades rotate the top blade anti-clockwise. The Original True Angle replaces every triangle, protractor, try square, bevel square, rafter square, framing square, combination square, or any other angle making template presently manufactured anywhere in the world. Made of special plastic the True Angle is virtually unbreakable.