This Crystal® ThermoBlok™ aluminum sliding patio door series features a high-performance frame structure, an innovative polyurethane thermal barrier technology that thermally breaks conductivity of the aluminum frame to substantially reduce thermal transfer from exterior of the door frame to interiors, and “intercept” warm edge glass spacer technology. These integrated features reduce heating and cooling loads on HVAC systems, providing long term energy efficiency and utility savings to property owners. Coordinating side light and architectural transoms and decorative between-the-glass grids make this series popular with homeowners. Knock-down (KD) frame for easy handling and transport. All KD doors are pre-notched and drilled for fast and easy assembly.