The specially roll-formed Impasse Rail is designed to be stronger than conventional rails. Pointed security spikes along the top front surface between pales prevent climbing. The specially roll-formed Impasse "I-Beam" is designed to withstand significant bending forces applied laterally in opposition to its major axis. STALWART ANTI-RAM SYSTEM The specially roll-formed Impasse Rail acts as a tray for carrying a 1" diameter steel cable that runs continuously from terminal to terminal in an installed fence line. Multiple rails can be attached (at lower end of panel) to carry multiple cables. With a two rail Stalwart cable system integrated into the Impasse fence, a 15,000 pound vehicle traveling 40 mph has been stopped within 1 meter.Department of State Certification PDF Impasse Stalwart Specification DOC Standard Practice for Installation DOC StylesGauntletStrongholdTrident