Accu-Glass’ borosilicate glass viewports 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 viewports are designed and built for both high and ultrahigh vacuum applications 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.