Atlona LinkConnect Plenum HDMI Cable When performance and safety can"t be compromised, you need Atlona LinkConnect Plenum HDMI cables. These cables combine the legendary performance of Atlona LinkConnect cables with the stringent UL certifications required for installation in plenum and riser air spaces. Atlona Performance When it has to work perfectly, trust Atlona. We were the first to sell plenum HDMI cables, and these 2nd generation cables raise the bar with better performance. We used 24 AWG copper for highest bandwidth and most reliable performance. Internal Enhancement The 50 and 75 foot versions utilize advanced chip technology to make sure your images are as clear as if they were next to the source! These self-powered enhancers eliminate speckles and dropouts. (The 50 ft. and 75 ft. cables are directional so the correct end must be connected to the display.) Plenum Cable Due to the hazards of smoke inhalation many building codes require "plenum" certified cables when installed above drop ceilings. These cables are also approved for use between floors. Check local building codes for rules in your area.