ResMed Airfit F40 QuietAir CPAP Vent Ring ReplacementQuietAir vent ring on your AirFit F40 full face mask? You dont need to buy a whole new mask, simply replace your worn or damaged vent ring to save money, reduce waste and continue enjoying its features: Generates just 20 decibels1 Limits noise2,3, so less likely to disturb you or your bed partner, helping you to stay on therapy4 In a study, more than 90% of patients said AirFit F40 was quiet and the air flow from the vent didnt disrupt their partners