A respiratory inlet having a mask end and a fitting end is provided. The respiratory inlet also includes a cavity and an exterior mating surface. The exterior mating surface is disposed proximate the fitting end, and is configured to matingly accept a first type of air supply fitting. The first type of air supply fitting is configured as a female fitting, and the respiratory inlet is configured to operate in a first mode when the female fitting is mated to the exterior mating surface. The cavity includes an opening oriented toward the fitting end, and an interior mating surface configured to matingly accept a second type of air supply fitting. The second type of air supply fitting is configured as a male fitting, and the respiratory inlet is configured to operate in a second mode when the male fitting is mated to the interior mating surface.