The “fit on the face” is the difference between AirFit F30 and AirFit F20.

The ResMed AirFit F30 Mask is designed with ‘no support’ on top of the nose. AirFit F30 poses no risk of strain on the bridge of nose. Therefore does not make no red marks or discomfort.

ResMed has designed AirFit F20 to cover the mouth and nose. Though AirFit F20 covers the nose completely, only some may feel strain on the nasal bridge.