Quality British made Captain Fields Pattern Parallel Rules. Precision injected mouled in 5mm acrylic, with divisions for the protractor and compass points, giving greater accuracy.Bevelled on all 4 edges for ease of use.Standard 16" (400mm) length with anodised aluminium link armsDeluxe 16" (400mm) length with solid brass link armsDeluxe 24" (600mm) length with solid brass link arms