INvent Retro-XLT series aluminum windows replicate the look of classic steel and wood windows, while offering modern, high performance. The windows feature a narrow, exterior face in beveled, ogee, cove, and square profiles, and a 2 1/2-, 3 1/2- and 4 1/2-in. frame depths. With polyamide thermal barriers and double insulating glass, the windows provide a U-factor as low as 0.39 and a CRF as high as Frame 60/Glass 70. Available as fixed, project-out awning, project-in hopper, or casement, the windows are NFRC labeled and AAMA AW-100 Performance Class.