Abstract: An excess flow valve including: (a) a housing including: an inlet portion; and ii) an outlet portion coupled to the inlet portion to define an interior having a passageway between an inlet and an outlet, wherein at least one of the inlet and outlet portion defines a valve seat and an annular channel; and (b) a unitary plunger including: a valve portion defining an aperture; a rim surrounding the valve portion; and an expandable portion extending between the valve portion and the rim, wherein the rim seats within the annular channel to fix the plunger such that the valve portion is set apart from the valve seat for allowing the passageway to be normally open, and as a flow through the fluid passageway exceeds a predetermined level, the expandable portion extends so that the valve portion couples to the valve seat to at least partially close the passageway.