These factory calibrated switches can be adjusted to your exact requirements. A polyimide diaphragm makes it compatable with gases, oils and all types of fuels. Has normally closed and open terminals.

VDO Adjustable Pressure Switch 3.1-7psi
Contains N/O and N/C contacts. 1/8″ NPT Thread. Preset at 4psi
Commonly used for staging Fuel Pumps, Cutting Ignition with loss of Oil Pressure, etc