This inexpensive portable titration set features a 2mm straight stopcock with PTFE plug. The borosilicate glass buret is filled by pressure supplied by the rubber bulb. A small hole in the filling tube at the "O" line permits setting of the liquid level and excess titrant is returned to the bottle. Complete Set furnished with buret, bottle (LG-4230-120 or LG4230-124), rubber hose, rubber stopper (LG-10392-126 or LG-10392-130), and rubber bulb (LG-4340-100). Accessories: Vent Tube (LG-4230-130) Scientists rely on the expertise and artistic skills of Wilmad-LabGlass' engineers and glass specialists to manufacture NMR and EPR consumables and laboratory glassware of the highest quality. Used daily in academia, healthcare and chemical, petroleum and other industrial applications, Wilmad offers 7000+ items as part of their standard catalog as well as custom fabrication for individual glassware, glass repair services and OEM glass parts.