This 12” (300mm) Verulam Triangular Metric ’A’ Scale Rule from Bludell Harling is professional quality and manufactured to the highest standard under controlled conditions. The measurement markings have exceptional clarity and legibility as well as unequalled accuracy and design. The material this scale rule is produced from was specifically chosen for its toughness and stability. Features the scales: 1:1, 1:10x1:2, 1:20, 1:5, 1:50x1:100, 1:200, 1:500, 1:1000x1:1250, 1:2500