Abstract: An apparatus for dispensing product from a container in which first and second members are provided in a vessel which is disposed in the container. The first member defines with the vessel a first chamber, and the second member defines with the first member a second chamber. One of the members moves in response to the pressure in the container to a first position relative to the other member and pressure is exerted in the second chamber on said first member to move it to a second position in response to the pressure in the container decreasing below the predetermined pressure. When the first member moves to the second position the first chamber is connected with the container to permit the pressurized gas in the first chamber to pass to the container and when the first member moves to the first position this connection is disconnected to prevent the passage of the gas.