ResMed · Under the nose full face mask (hybrid, minimal contact)
ResMed AirFit F40
ResMed's smallest tube-down full face mask. Its AdaptiSeal silicone cushion rests under your nose and around your mouth, a short tube connects at the front, and the headgear has magnetic clips and fewer adjustment points than the F20.
The AirFit F40 has magnetic headgear clips. It was not one of the masks named in the FDA's January 18, 2024 safety communication on ResMed masks with magnets, but its own labeling carries the same contraindication ResMed adopted in its December 20, 2023 update: do not use it if you, or anyone in close physical contact with you while the mask is in use, has an active medical implant that interacts with magnets (such as a pacemaker, implantable cardioverter defibrillator, neurostimulator, cerebrospinal fluid shunt, or insulin or infusion pump) or a metallic implant or object containing ferromagnetic material (such as aneurysm clips, embolic coils, stents, valves, electrodes, certain hearing or balance implants, ocular implants, or metallic splinters in the eye). Keep the mask magnets at least 6 inches (150 mm) away from any implant or medical device that may be affected by magnetic interference. If this applies to you or a bed partner, stop using the mask and ask your clinician or mask provider for a mask without magnets. The F40 user guide adds that the magnets are in the frame and lower headgear clips, have a field strength of up to 400 mT, and may detach while you sleep.
Usually suits
- Mouth breathers who want the smallest full face option
- People who wear glasses in bed
- People with marks or sores on the bridge of the nose
Design
- UltraCompact under-the-nose AdaptiSeal silicone cushion
- Short tube and quick-release elbow at the front
- Magnetic clips in the frame and lower headgear straps
- QuietAir vent ring, with a multi-hole vent ring alternative
- Low profile that lets you wear glasses in bed
Strengths and trade-offs
- Very small footprint for a full face mask, with nothing on the bridge of the nose
- Fewer headgear adjustment points make it quicker to put on
- Glasses can be worn for reading or TV with the mask on
- Contains magnets, with ResMed's implant contraindication
- Tube connects at the front, so you may want a hose hanger or tube routing for side sleeping
- ResMed's user guide says to select 'Pillows' in the mask setting on ResMed machines, which is easy to miss
- Daily cleaning covers more small parts (cushion, short tube, elbow and vent ring)
Finding your size
Choose the cushion with ResMed's AirFit F40 fitting template, printed at 100% scale, or with your supplier. Complete masks come as cushion and headgear pairs (for example Medium cushion with Standard headgear, or Medium with Small headgear). The user guide warns that sizing is not the same across different masks, so do not assume your old mask size carries over.
How to fit it
Release the clips
Twist and pull both magnetic clips away from the frame magnets.
Place the cushion under your nose
Set the cushion under your nose so it sits comfortably against your face. With the ResMed logo on the headgear facing out, pull the headgear over your head. The top strap should sit on top of your head, not too far forward or back.
Attach the lower straps
Bring the lower straps under your ears and snap the magnetic clips onto the frame.
Adjust only if needed
If the mask needs adjusting, undo the tabs on the upper straps and pull evenly, then repeat with the lower straps. Do not overtighten, because that can cause redness or sores around the cushion.
Set your machine and check
Connect the tube and turn the machine on. On a ResMed machine, make sure the mask setting is 'Pillows', as the F40 user guide instructs.
Common problems and fixes
Leak at the sides of the nose
Re-center the cushion under your nose and adjust the upper straps evenly. If it persists, ask your supplier to recheck the cushion size, because F40 sizing differs from other masks.
Clips come off during the night
ResMed notes the magnetic clips may detach while you sleep. Check the clips are fully seated and the lower straps are not so loose that rolling over pulls them off.
Machine shows higher leak than expected
Check the mask setting on your ResMed machine is 'Pillows' as the user guide says, and that the vent ring is clean and clear.
Cleaning and care
Daily, take off and clean the cushion, elbow with short tube, and vent ring: soak them in warm water with a mild liquid detergent (no air bubbles trapped), shake them and hand wash with a soft brush, paying attention to the vent holes. Rinse under running water and air dry on a towel out of direct sunlight. Weekly, wash the headgear and frame the same way and squeeze excess water out of the fabric. ResMed says not to use a dishwasher or washing machine, and that ozone or UV products have not been validated for this mask.
How often to replace parts
- Mask
- Up to 1 complete mask every 3 months (Medicare A7030)
- Cushion
- Up to 1 per month (Medicare A7031, full face cushion)
- Headgear
- Up to 1 every 6 months (Medicare A7035)
Supplies that can help
A simple hook or hanger for drying CPAP tubing vertically after washing, and for keeping it off the floor.
Pre-moistened wipes for a quick daily wipe of the mask cushion, mostly to remove skin oils between proper washes.
Plain, mild dish soap is the cleaning agent most CPAP makers and the FDA point to for masks, tubing and humidifier chambers.
A pillow with cutouts or a contoured edge so a mask and hose are not pushed out of place when you sleep on your side.
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Frequently asked questions
Why does ResMed say to set my machine to Pillows for the AirFit F40?
The AirFit F40 user guide instructs you to select 'Pillows' in the mask setting on your ResMed device, even though it is a full face mask. Follow the guide, and ask your supplier if your machine's menu looks different.
Can I wear glasses with the AirFit F40?
Yes. ResMed designed its low profile so you can wear glasses to read or watch TV in bed while using therapy.
Is the AirFit F40 the same size as my AirFit F20?
Not necessarily. The F40 user guide warns that sizing across different masks is not always the same, so use the F40 fitting template or get sized by your supplier.
Does the AirFit F40 have magnets?
Yes, in the frame and the lower headgear clips. It is contraindicated if you or someone in close contact with you while it is in use has a pacemaker, defibrillator or other implant on ResMed's list.
Sources
Last reviewed October 11, 2026. How we research · Report an error