An assembly, comprising: a pressure regulator comprising a first housing, an adjustment spring moveably disposed within said first housing and comprising a first end and a second end; and an adjuster cap for adjusting an output pressure of the pressure regulator, said adjuster cap disposed in said first housing and in physical contact with said first end of said adjustment spring; wherein said adjuster cap is formed to include a plurality of key slots (510,512) therein; a pressure regulator adjustment tool comprising a second housing formed to include a first bore extending therethrough, a rotatable adjuster piston moveably disposed within said first bore, wherein said adjuster piston comprises a plurality of alignment keys (160,162) disposed on a distal end thereof, wherein each of said plurality of alignment keys is removeably disposed within a different one of said plurality of key slots, wherein: said adjuster piston is attached to a rotatable adjustment knob; rotating said adjustment knob in a first direction causes said adjuster piston to rotate and move downwardly in said bore that causes said adjustment spring to compress and increase the output pressure of the pressure regulator; and rotating said adjustment knob in a second and opposite direction causes said adjuster piston to rotate and move upwardly in said bore that causes said adjustment spring to elongate and decrease the output pressure of the pressure regulator. a pressure regulator comprising a first housing, an adjustment spring moveably disposed within said first housing and comprising a first end and a second end; and an adjuster cap for adjusting an output pressure of the pressure regulator, said adjuster cap disposed in said first housing and in physical contact with said first end of said adjustment spring; wherein said adjuster cap is formed to include a plurality of key slots (510,512) therein; a pressure regulator adjustment tool comprising a second housing formed to include a first bore extending therethrough, a rotatable adjuster piston moveably disposed within said first bore, wherein said adjuster piston comprises a plurality of alignment keys (160,162) disposed on a distal end thereof, wherein each of said plurality of alignment keys is removeably disposed within a different one of said plurality of key slots, wherein: said adjuster piston is attached to a rotatable adjustment knob; rotating said adjustment knob in a first direction causes said adjuster piston to rotate and move downwardly in said bore that causes said adjustment spring to compress and increase the output pressure of the pressure regulator; and rotating said adjustment knob in a second and opposite direction causes said adjuster piston to rotate and move upwardly in said bore that causes said adjustment spring to elongate and decrease the output pressure of the pressure regulator. said adjuster piston is attached to a rotatable adjustment knob; rotating said adjustment knob in a first direction causes said adjuster piston to rotate and move downwardly in said bore that causes said adjustment spring to compress and increase the output pressure of the pressure regulator; and rotating said adjustment knob in a second and opposite direction causes said adjuster piston to rotate and move upwardly in said bore that causes said adjustment spring to elongate and decrease the output pressure of the pressure regulator.