F20 Sizing Guidehttps://www.resmed.com/us/dam/documents ... er_eng.pdf
You can print your ResMed sizing guide here. Remember to print to scale, as you’ll have to trim your guide from the paper.
While in front of a mirror, hold your sizing guide to your face. The top of the guide should correspond with the top of your nasal bridge.
The lower part of the guide indicates which mask size is best for your face. The size that aligns with the crease below your lower lip will be your best fit.
If you’re between sizes, we recommend selecting the larger option for greater comfort.