[PREMIUM QUALITY] This engineering triangle scale is made of anodized aluminum alloy, very solid and sturdy. Designed for maximum durability, this 3 sided metal architect ruler is perfect for lasting use [PRECISE IMPERIAL SCALE] The aluminum triangle ruler is professional grade with supreme accuracy. With reliable construction and accurate performance, the black construction ruler is ideal for architects, engineers, draftsmen and students [TRIPLE SIDED DESIGN] The classic architect's triple-sided scale included: 1-1/2", 1, 3/4", 3/8", 3/16", 3/32", 1/2", 1/4", 1/8", 3, 16, very convenient and useful for professional use [LASER ETCHED TECHNOLOGY] All numbers and measurement markings on drafting scale rulers are laser etched for maximum clarity and readability. Laser etched technology effectively prevents scale numbers and markings from wearing off or fading away [SATISFACTION GUARANTEE] If you are unsatisfied with your purchase, we will offer a full refund, no questions asked