Nalgene 2158 Polypropylene Quick Filling-Venting Closures. Ported 83B closure features quick disconnect fittings and inside/outside barbed tubulations. Forms a convenient fluid transfer system with the tubing of your choice. Available in 2 or 3 port styles for 1/4" or 3/8" tubing. Socket fittings in cap have internal valves that seal when a tubulation fitting is removed so container seal integrity is maintained. Excellent for use in vacuum systems with Nalgene Heavy Duty Carboys and Bottles. Use with Nalgene 180 heavy-wall tubing. Polypropylene closure and fittings, TPE gasket.