Invented by a practicing architect, the AlumiDrafter combines the advantages of a traditional trianglular scale with many other drafting features. This multi-use tool gives users the ablility to read eight different blueprint scales using the innovative window feature and also offers a compass ruler that can be used to draw perfectly accurate circles and arcs. Finally, the angle guide on the back allows the user to draw accurate angle lines and triangles. Calibrations are in inches and centimeters.