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