Plastic Triangular Ruler – with 6 Metric Scales (1:75, 1:100, 1:125, 1:25, 1:50, 1:20) This high-precision plastic triangular scale ruler is a must-have tool for architects, engineers, draftsmen, and students involved in technical drawing or design. Designed for accuracy, durability, and convenience, this 3-sided ruler features six clearly marked metric scales that allow you to seamlessly switch between different drawing requirements without needing multiple tools. Whether you're working in architectural design, construction planning, engineering layouts, or scale model building, this scale ruler delivers unmatched performance and clarity. The triangular shape ensures stability on flat surfaces and allows quick rotation from one scale to another. With bright color-coded grooves (red and yellow) for easy identification, you can speed up your workflow and reduce mistakes when switching scales.