These borosilicate glass plain chromatography columns have a Standard Taper 24/40 outer joint at top. A coarse porosity fritted disc is sealed into column just above straight bore stopcock with PTFE plug at bottom. 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.