The invention relates to a multifunctional applicator for mobile use having an applicator plug, a supply tube, a Y-piece, fork tubes and a nose piece with prongs, wherein the applicator plug comprises a pressure chamber that has a humidifier interface for connection with a high flow therapy device, an oxygen supply port having an opening diameter of at least 1 mm, and a therapy air supply port for the supply tube, the humidifier interface and the oxygen supply port within the pressure chamber each having an upper and a lower valve seat that are provided with a seal and a valve body being movable between said valve seats and said valve body being subjected to a force by a helical compression spring from the direction of the oxygen supply port and on the other hand being pushed against the upper valve seat by an actuating element of the high flow therapy device when the applicator plug is locked in place on the high flow therapy device.
