The ResMed Mirage Swift / Mirage Swift II Tube Retainer connects to the Mirage Swift / Mirage Swift II Short Tube and to the Mirage Swift / Mirage Swift II headgear to keep the tube in place when you choose to position the tube over the head, essentially acting as a hose guide. The tube retainer is not needed if you chooses to place the tube away from the head towards the body.