EBayFeatures: Material: This engineering triangle scale ruler is made of anodized aluminum alloy, very solid and sturdy. Laser-etched markings: The scale ruler is precisely marked, making your drafts, designs, blueprint more accurate. Durable and reliable: Designed for maximum durability, this metal architect ruler is suitable for lasting use. Application: The architectural scale ruler is suitable for architects, engineers, draftsmen, builders, roofers, teachers and students, etc. Specifications: Size: Triangular scale engineer ruler: 12 inch/ 30 cm, 30/ 60 degree triangular ruler, 45/ 90 degree triangular ruler, a protractor and a 15 cm ruler Types of technology: laser etched Material: metal, anodized aluminum alloy Package contents: 2 x Triangular architect scale rulers 2 x Triangular rulers 1 x 15 CM ruler 1 x Protractor Warm Note: This set is in metric Package includes: 6 pieces in total, which contains 2 12 inches/ 30 cm aluminum triangular rulers, 1 30/ 60 degree triangular ruler, 1 45/ 90 degree triangular ruler, 1 protractor, 1 5.9 Inches/ 15 cm ruler Material: the scale ruler set is made from pure aluminum mixed with other elements to create a high-strength alloy, and the triangular ruler is durable, lightweight and reliable Relative advantage: the laser-etched markings that won't rub off or fade, the ruler itself is made of solid anodized aluminum, unlike flimsy alternatives that contain plastic High contrast: white-on-black design makes each line and number significantly easier to read, ultimately preventing unnecessary eye strain Target customer: with reliable construction and accurate performance, the black construction ruler is appropriate for architects, engineers, draftsmen and students