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Zero-Length Viewports

Corning 7056 - Borosilicate Glass - Viewports, drawing

Zero-Length Borosilicate Glass Viewports

Accu-Glass’ Zero-length Borosilicate glass viewports are ideally suited 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 viewports are designed for both high and ultrahigh (HV and UHV) vacuum applications and employ the latest in glass-to-metal bonding technology to hermetically seal Borosilicate glass to expansion-matched 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 350°C
  • HV and UHV compatible construction
  • Conflat CF, and ISO NW compatible mounts
  • Stainless steel and Kovar construction
  • Custom Solutions on Request