A device for providing respiratory therapy to a patient comprising: a first elongated lumen having a constant internal diameter, the first lumen having an inlet end and an outlet end; a second elongated lumen having a constant internal diameter, the second lumen having an inlet end and an outlet end; and a nosepiece portion configured to be connected to the outlet ends of the first and second lumens, the nosepiece portion having: a third lumen having a constant internal diameter equal to the constant internal diameter of the first lumen, the third lumen having an inlet end adapted to be connected to the outlet end of the first lumen without constricting the internal diameter of the first lumen, the third lumen configured to receive a first flow of breathing gas from the first lumen and deliver the first flow of breathing gas to an outlet end of the third lumen; and a fourth lumen having a constant internal diameter equal to the constant internal diameter of the second lumen, the fourth lumen having an inlet end adapted to be connected to the outlet end of the second lumen without constricting the internal diameter of the second lumen, the fourth lumen configured to receive a second flow of breathing gas from the second lumen and deliver the second flow of breathing gas to an outlet end of the fourth lumen, the second flow of breathing gas maintained separate from the first flow of breathing gas within the nosepiece portion, characterized in that the first lumen and the nosepiece portion define a constant diameter flow path for the first flow of breathing gas from the inlet end of the first lumen to the outlet end of the third lumen, and wherein the second lumen and the nosepiece portion define a constant diameter flow path for the second flow of breathing gas from the inlet end of the second lumen to the outlet end of the fourth lumen. a first elongated lumen having a constant internal diameter, the first lumen having an inlet end and an outlet end; a second elongated lumen having a constant internal diameter, the second lumen having an inlet end and an outlet end; and a nosepiece portion configured to be connected to the outlet ends of the first and second lumens, the nosepiece portion having: a third lumen having a constant internal diameter equal to the constant internal diameter of the first lumen, the third lumen having an inlet end adapted to be connected to the outlet end of the first lumen without constricting the internal diameter of the first lumen, the third lumen configured to receive a first flow of breathing gas from the first lumen and deliver the first flow of breathing gas to an outlet end of the third lumen; and a fourth lumen having a constant internal diameter equal to the constant internal diameter of the second lumen, the fourth lumen having an inlet end adapted to be connected to the outlet end of the second lumen without constricting the internal diameter of the second lumen, the fourth lumen configured to receive a second flow of breathing gas from the second lumen and deliver the second flow of breathing gas to an outlet end of the fourth lumen, the second flow of breathing gas maintained separate from the first flow of breathing gas within the nosepiece portion, a third lumen having a constant internal diameter equal to the constant internal diameter of the first lumen, the third lumen having an inlet end adapted to be connected to the outlet end of the first lumen without constricting the internal diameter of the first lumen, the third lumen configured to receive a first flow of breathing gas from the first lumen and deliver the first flow of breathing gas to an outlet end of the third lumen; and a fourth lumen having a constant internal diameter equal to the constant internal diameter of the second lumen, the fourth lumen having an inlet end adapted to be connected to the outlet end of the second lumen without constricting the internal diameter of the second lumen, the fourth lumen configured to receive a second flow of breathing gas from the second lumen and deliver the second flow of breathing gas to an outlet end of the fourth lumen, the second flow of breathing gas maintained separate from the first flow of breathing gas within the nosepiece portion, characterized in that the first lumen and the nosepiece portion define a constant diameter flow path for the first flow of breathing gas from the inlet end of the first lumen to the outlet end of the third lumen, and wherein the second lumen and the nosepiece portion define a constant diameter flow path for the second flow of breathing gas from the inlet end of the second lumen to the outlet end of the fourth lumen.