Commercial windows generally need to be more resilient and dimensionally stable than their residential counterparts because of their size and placement in high-traffic areas. Kolbe Windows & Doors’ Kolbe 4500 Series features a galvanized steel reinforced uPVC frame and sash. Its extrusions comprise multiple chambers with thick walls to improve energy performance while stabilizers and impact modifiers in the material protect against fading from solar radiation. The doors joints are fusion-welded to create an impervious seal. Tilt turn, fixed, tilt-and-slide, and outswing hinged models are available. The series is offered in two frames: one for the North American market with a frame depth of 3 ¼” and one for the European market with a depth of 2 3/8”.