M+R SCALE RULER 1:20:25:331/3:50:75:100

The M+R scale ruler with scales 1:20, 1:25, 1:331/3, 1:50, 1:75, 1:100 is a specialized drawing tool primarily used for accurately representing dimensions at various scales.

These scales allow architects, engineers, and designers to convert real-world dimensions into scaled-down or scaled-up versions on drawings. Each side of the scale ruler is marked with different measurements, making it quick and easy to switch between various ratios.