Trianguler 30cm scale ruler ideal for use in architecture and mechanical engineering.
- Engineering scale ruler has the reductions 1: 2.5: 5: 10: 20: 50: 100.
- Architecture scale ruler has the reductions 1:20: 25: 50: 75: 100: 125.
- Student scale ruler has the reductions 1:20: 25: 33 1/3: 50: 75: 100.