Infrared Window, Optic Maximum Temperature 2,552 Degrees F, Viewing Aperture Area 2.5 sq in, Viewing Aperture Diameter 1.8 in, Viewing Aperture Height Not Applicable, Viewing Aperture Width Not Applicable, Window Thickness 0.08 in, Body Maximum Temperature 1,218 Degrees F, Includes (4) Fixing Screws, Access Key, Drilling Template, IP Rating IP65, Gasket Maximum Temperature 482 Degrees F, Crystal Insert Diameter 2 in, Crystal Insert Height Not Applicable, Crystal Insert Width Not Applicable