The Vintage Staedtler-Mars 987 18-31 Architect Triangle Drafting Ruler is a collectible engineering tool measuring 12 inches. Made by Staedtler-Mars, a reputable brand known for quality drafting tools, this ruler is a classic piece for any enthusiast or professional in the field of architecture and engineering. Imported from China, this triangle drafting ruler is a precise and versatile tool that has stood the test of time in the industry.