?IMPORTANT NOTE?Include 2 pack replacement headgear ONLY. headgear belongs to consumable products, and it is recommended to replace the headgear after 3-6 months of use. ?BETTER SEAL?The head strap fits your brain, which greatly increases stability. So that you do not have any leaks from the ventilator or sleep apnea mechine. ?STRONG ADHESION & DURABLE?This durable headgear adopts sticky paste strap system, so it is so easy to attach. Futhermore, it could be washed repeatedly without fraying, shedding or other forms of degradation. ?SOFT COMFORTABLE MATERIAL?nasal and full face headband is made of the advanced grade fiber which is strong, sterile. Ultralight comfort to wear. Better elastic, sweat-absorbent, breathable and tasteless. Great replacement strap for your sleep!. ?WIDE COMPATIBILITY?Our universal replacement headgear strap is compatible with ResMed Fx Mirage Quattro Air Fit and 4-point full face mask. Also it has a wide variety for ResMed AirFit F20 N10. But you have better see the specific usages of the head strap in the third picture.