4-1/2 in Round Infrared Window Crystal Insert Size 95mm dia Viewing Aperture Size 89mm dia Viewing Aperture Area 6221 sq mm Window Thickness 4 mm NEMA Rating 12 4 IP Rating 67 Gasket Maximum Temperature 76.7 Degrees C (170 Degrees F) Body Maximum Temperature 510 Degrees C (950 Degrees F) Optic Maximum Temperature 1355.6 Degrees C (2474 Degrees F) Voltage Range Any Components Anodized Aluminum Frame and Cover Body Material Aluminum Includes Installation Instructions