12” Triangular Architect Scale Ruler Architectural Scale (Imperial Measurements) - Ideal for Architects, Engineers, Draftsman and StudentsTriangular Architectural Scale Ruler, 3 Sides With 6 Different Scales. IMPERIAL SCALES TRIANGULAR 3 SIDES 1 1 2", 1, 3 4",3 8", 3 16", 3 32", 1 2" 1 4", 1 8", 3, 16 PROFESSIONAL GRADE SOLID PLASTIC CORE Heavy Duty Solid Construction eliminates flex and lays flat for Perfect Lines & Measurements. COLOR CODED GROOVES For Quick Scale Identification CONCAVE DESIGN Features Smudge Proof Concave Design to Keep Drawings Clean Good for students and