The Aluminum (Al) mirrors in this catalog are a special kind of Al mirrors constructed of monolithic aluminum blocks without the further deposition of reflection coatings, the reflective nature of these aluminum mirrors derives from the concave shapes and the polishing procedure. North Optics's aluminum mirrors find prominence in thermal imaging systems with long focal lengths, such as continuous zoom lenses and double FOV lenses. The operation wavelength range of our Al mirrors covers the MWIR (3-5 micro) and LWIR (8-12 micro) wavelength ranges.