A special scale that changes our perception of other rules! Widely used by drafting professionals, Alumicolor Solid Triangular Drafting Scales are made of extruded aluminum. A special photo-anodizing process incorporates the ruler's calibrations into the aluminum to provide a smooth, tick-free finish and markings that are resistant to cleaners and solvents. Available in metric or Imperial calibrations. Comes with its own protective plastic case.