Please note: If using an antibacterial filter, it must be checked for signs of moisture or other contaminants, particularly during humidification. Failure to do so could result in increased breathing system resistance. Further instruction for using Stellar with an external humidifier: Place the antibacterial filter at the air outlet, connect the external humidifier to the other side of the AB filter through the air tubing. Connect the other air tubing from the humidifier to the ResMed leak valve. Do not use an antibacterial filter with the internal humidifier H4i. In addition, patients should follow ResMed’s user guide.