Devilbiss Long Life Air Inlet Filter can be used with Devilbiss Pulmo Aide Compressor Nebulizer System (code 5650D) and Devilbiss PulmoMate Compressor Nebulizer System (code 4650D). The filter should be changed once a month or when the filter turns gray in color. Pulmo Aide Compressor Nebulizer Filters are OEM filters from DeVilbiss. The Pulmo-Aide inlet filter is a long-life filter that removes harmful particles from the air to protect your compressor nebulizer. Pulmo Aide filters should be replaced on a regular basis to protect your health and the operation of your nebulizer compressor. Pack of 2