A pressure regulator is used to lower and stabilize the pressure from a gas or air source. The output pressure of most regulators is adjustable within a certain range, at the most up to the input pressure. There are several kinds of regulators made for different pressure ranges and gases, the most useful ones in spudgun application are:
Regulators are most commonly used for providing a safe pressure from high pressure sources for pneumatic cannons, pressurizing hybrids with an oxidizer, and to provide a fuel meter with a constant pressure from propane tanks. It is important that the regulator is made to handle the input pressure, as well as any special conditions (freezing form liquid gas, flammable/corrosive gases etc).