The Universal Window and Door 700 Series Historic Steel Replica windows are the ideal choice for historic buildings, featuring a narrow sightline that replicates the original putty glazed steel or wood windows to meet the exacting standards of historic commissions while keeping the structural integrity of the window intact. The 700 Series has been installed in dozens of projects that have been recognized by the National Park Service National Register of Historic Places as well as numerous state and local historic preservation entities. This award-winning window combines the corrosion resistance of aluminum construction combined with Super Spacer ®, the world's only patented TrueWARM ® edge technology, and offers dual-laminated systems to supply superior sound, impact and security performance. The increased energy efficiency in these steel replicas comes from the new warm edge technology, a patented process utilizing the latest low thermal transmission material that seals the multi-layered glass edges, and allows more protection from the temperature variation between the interior and exterior at the critical edge seal area. The windows feature a slide-on heavy-duty tie back clip – or strap anchor – that allows for a structurally sound installation without the need for through-frame anchors. The clips do not add to the narrow sightlines of the historic replica windows and allow for a structurally sound installation without the need for through-frame anchors. The aluminum thermally broken frame and sash, along with a 1 1/8-inch triple glaze capacity, have a .23 U-value in fixed applications and .35 U-value in vent windows. Universal's warranty of this new technology is a full fifteen years, as opposed to the five to ten years offered by other manufacturers.