Glass Viewport Introduction
Glass viewports are an economical, practical and common solution for vacuum observation ports.  Glass viewports are typically sealed to low expansion nickel-iron alloys or 300 series stainless steel metal sleeves using the latest in glass-to-metal bonding technology.  The material in MDC Precision glass viewports is Corning 7056 glass, the most commonly used vacuum window material in the industry. 
Specifications
•	Zero-length offers greater distortion-free view area
•	>90% Transmission from 360nm to 2300nm
•	CF and weld mount bakeable to 400°C, 10°C/Min gradient
•	ISO Kwik-Flange® and Large Flanges bakeable to 200°C, 10°C/Min gradient
•	Optional AR Coatings available
•	Mounting style: Conflat Flange (CF 1.33")
•	Fastening Method: Bolts
•	Holes size: 0.172"
•	Lens grade: 7056
•	Lens thickness: 0.070"
•	View diameter: 0.720"