Aluminum 6" 4 bevel combination architect and engineer scale. The architect and engineer 4 bevel scales are an upscale precision drafting tool. Professionals will be pleased to own and use these quality scales which are made from extruded aluminum. The ultra smooth edges with photo anodized calibrations allow for lines to be drawn that are smooth, straight and tick-free. Calibrations: (1/8, 1/4), (1/16, 1/32), 30, 50 parts per inch.