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ISO-Flanged Zero-Length Viewports

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Zero-Length ISO Viewports

7056 Viewports - ISO KF / LF Flanges

Accu-Glass’ Zero-length Borosilicate glass viewports mounted on ISO NW KF/LF flanges are ideal for general purpose use such as the direct observation of processes inside a vacuum chamber. The window material is a Corning 7056 type Borosilicate glass — one of the most common materials used in the construction of vacuum viewports. Our zero-length ISO viewports are designed and built for high vacuum applications for service to 1x10E-8 Torr and employ the latest in glass-to-metal bonding technology to hermetically seal Borosilicate glass to nickel-iron alloy sleeves. Since glass is susceptible to scratching and inherently weak under point stresses, caution must always be exercised when handling these viewports. Proper handling of glass viewports and components will greatly minimize the chance of implosion hazard.


  • Corning 7056 Type Borosilicate glass
  • Expansion-matched Kovar (Ni-Fe-Co) transition metal
  • High temperature rated to 200°C
  • HV compatible construction
  • ISO NW compatible mounts
  • Stainless steel and Kovar construction
  • Custom Solutions on Request


Custom Solutions on Request

7056 Borosilicate glass substrate transmission curve graph