Alumicolor triangular Drafting Scales are made of professional-quality extruded aluminum. Alumicolors 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. Graduations: 16, (1/8, 1/4), (1/2, 1), (3/8, 3/4), (3, 1-1/2), (3/32, 3/16)