Imperial triangular scale ruler has 3 sides with 6 different scales which are used for various professional applications, architecture, engineering, and technical illustration, designers, artists, builders, etc for supreme accuracy. It has precise scales of 1:20, 1:25, 1:50, 1:75, 1:100, 1:125 inches. The Color-coded grooves for quick and accurate selection of the desired scale. It is perfect to carry everywhere and protect from dust and spots. Avoid ruin your blueprints and homework and the user can work without any worries