Alumicolor triangular Architects Drafting Scales are made of extruded aluminum. Alumicolor's photo anodizing process makes the calibrations a part of the aluminum, providing a smooth, tick-free finish and markings which are resistant to cleaners and solvents. Hollow Scales are lightweight for easy portability and a more affordable price. The scale has the following calibrations 16, (1/8,1/4), (1/2, 1), (3/8, 3/4), (3, 1 1/2), (3/32, 3/16).