These Sample-Seal U-tube liquid sample holders are used to store precursors that generate vapors to be flowed into the vacuum chamber. These U-tube liquid sample holders include two 0 to 4 mm adjustable high-vacuum valves which produce a leak-tight o-ring seal with O-Ring and Pinch Clamp. They are designed with 0.625 inch OD on the glass straight sections before the U-shape and include inlet and exhaust ports of #15 O-ring joint flange glass connections. 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. They are about 10 inch long being 2 inches wide (outside edge of glass u-shape) with #15 O-ring joint glass flange connections. For connections at the #15 glass joint flange they require a #15 O-Ring and pinch clamp size of No. 28 sold on this website. Replacement o-rings and pinch clamps are sold separately, please call 505-872-0037 for more information.