Handle your NMR sample without flame sealing your tubes. Teflon covered O-Ring eliminates material incompatibilities and completely greaseless Teflon assembly means the tube is easy to use and to disassemble for cleaning. Includes female joint for quick attachment to your vacuum rack. Available in Beige, Blue, Green, Orange, Red and Yellow. A Vacuum level of 1 x 10-6 mbar can be achieved with this valve. Internal positive pressure rating = 1 bar (14.7 PSI)