Accu-Glass dual-flange glass adapters are offered in 7052 Borosilicate or 7740 Pyrex glass. They are fitted with low-expansion Nickel-Iron (Kovar®), and stainless steel metal transitions respectively. These flanged adapters are ideally suited for high and ultrahigh vacuum applications where electrical break and/or isolation between components is required. Available in four (4) glass tube sizes including 1/2, 3/4, 1-1/2 and 2-1/2 inch diameters. NOTE that glass-to-metal sealing is more of an art than a science, and as such (other than mounting flange dimensions) all dimensions are nominal, and for reference only. Glass dimensions (overall lengths) can vary significantly from one assembly to another.