Accu-Glass open, single-flange glass adapters are constructed with 7740 Pyrex glass. They are available with low-expansion Nickel-Iron (Kovar®) or stainless steel metal transitions. These open end adapters are ideally suited for high and ultrahigh vacuum applications where joining to other laboratory glass or apparatus 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.