Abstract: Devices that can be used to recover hydrocarbon production from closed-in oil wells capable of building up wellhead pressure and/or to sustain marginal oil production in oil wells are disclosed. Production in oil and natural gas producing wells in mature fields that have the ability to build up wellhead pressure and where the depletion of reservoir pressure has caused low or zero productivity may be automated. The devices include at least two bellows that facilitate their operation. The bellows may close the well to build up pressure in the wellhead and open the well to flow line pressure.