The AirFit™ F20 Full Face CPAP mask is ResMed's most technologically advanced Full Face mask that features improved comfort due to innovative enhancements and a simple design. This mask is easy to use and reassemble.   Please follow this size guide to determine the most appropriate fit:  Size Guide Designed for a universal comfortable fit that is just right for you. Uses a soft, flexible frame, and magnetic clips for extra comfort and simplicity when putting on, using, or removing the AirFit™ F20 Full CPAP mask. Please note: For Medical implants that interact with magnets or metallic implants that are susceptible to magnets, it's advised that this mask is not used since it contains magnetic clips. Please consult with your physician before using these types of masks. For the version of this mask with non-magnetic clips, please follow this link here.