Abstract: A valve assembly has an outer body with an internal passageway for gas containing a valve seat and a valve member which can be lifted from the valve seat by rearward pressure. An inner body is threaded in the passageway, and itself includes an internal passage and a plunger within the passage. The plunger has a forward hollow sleeve portion and two arms extending rearwardly at diametrally opposite positions, the arms being linked at their rearward ends by a bridge from which extends an activating member adapted to hold the valve member away from the valve seat. The plunger has a sealing member forwardly of the activating member for closing the internal passage when the plunger is in a forward position. The inner body has two opposed grooves to receiving the arms, thus interlocking the plunger and the inner body so that rotation of the one requires rotation of the other. The bridge portion can be engaged by a forked tool for rotating it.