The primary objective of this study is to evaluate the subjective performance of the Menai mask systems (full face, nasal, and pillows variants), compared against Comparison mask systems.

The study will evaluate the subjective seal, comfort, stability, usability, and humidification performance of the prototype mask systems in CPAP established patients. The performance of the prototype Menai mask systems (full face, nasal, and pillows variants) will be subjectively assessed through user questionnaires based on an 11-point Likert scale, and will be compared against Comparison masks.

The prototype masks share the same parts (cushion, frame, headgear), with the difference being that the Menai masks feature a novel vent and humidification system.

Inclusion Criteria:

• Participants willing to provide written informed consent
• Participants who can read and comprehend written and spoken English
• Participants who are over 18 years of age
• Participants who have been diagnosed with OSA
• Participants who have been established on CPAP for ≥ 6 months
• Participants who are currently using the same mask type/variant as the interventional mask system to be evaluated

Exclusion Criteria:

• Participants who are not able to provide written informed consent
• Participants who are unable to comprehend written and spoken English
• Participants who are pregnant
• Participants who are unsuitable to participate in the study in the opinion of the researcher
• Participants with a pre-existing lung disease or a condition that would predispose them to pneumothorax (e.g. COPD, lung cancer; fibrosis of the lungs; recent (< 2years) case of pneumonia or lung infection, lung injury)
• Participants who cannot participate for the duration of the trial
• Participants who are established on bi-level support therapy
• Participants who are not currently using the same mask type/variant as the interventional mask system to be evaluated