Threaded both ends and with additional #7 threaded side opening for introduction of samples by hypodermic syringe. #7 thread at top is supplied with 5029 Nylon bushing and Fetfe O-ring for use with 5831, 5832 adjustable feed tubes. Size listed is Ace-thred designation which refers to I.D. of tubing above lower thread and corresponds to 5820 column diamater. Supplied complete with one silicone rubber septum and two Nylon busings with FETFE O-rings.