These are the replacement high-vacuum valve assembly designed for our Ideal Vacuum Sample-Seal U-tube shaped storage containers which are built from 5/8 inch OD glass tube. These replacement high-vacuum valves include the 2 Viton O-ring seals (additional replacement seals are also sold separately). These Sample-Seal U-tube liquid sample holders are used to store precursors that generate vapors to be flowed into the vacuum chamber. Our U-tube liquid sample holders require two each of these 0 to 4 mm adjustable high-vacuum valves which produce a leak-tight O-ring seal. These U-tube liquid sample holders are designed to withstand pressurizing up to 50 PSI and are often used in molecular spectroscopy experiment to contain the precursor liquid samples before the spectrometer. Please call 505-872-0037 for more information.