Viewing aperture diameter: 43 mm (1.7 in) Viewing aperture area: 1452 mm2 (2.25 sq in) Engineered and tested to withstand electric-arcs up to 50 kA for 30 cycles Certified by UL & CSA for Type 3/12 (Outdoor) environments in North America and Canada, the C-Range windows are tested to withstand the long term aging effects of UV exposure Certified by SIRA Certification IP65 (Outdoor) environments in Europe The CLIRVU coating—exclusive to Hawk IR Windows—seals the optic prior to assembly to protect against moisture degradation. Own a Fluke Camera? The Quadraband optic is IR-Fusion® compatible, allowing the thermographer to see potential problems in visual light and thermographic mode. Got more than one window per panel? Each C-Range window is delivered with an identification plate attached for unique, on-site numbering for rapid location confirmation and faster repairs Each infrared window comes complete with a security access key, installation instructions and self-adhesive drilling template.