AIM AND HYPOTHESIS: The purpose of this study is to monitor the bioburden and impedance characteristics of a prototype mask system and to evaluate the usability of the mask system. The mask system will be assessed according to objective data recordings and user questionnaires. It is hypothesised that the prototype mask components will not pose a health risk (with regards to bioburden and impedance) and that the mask system will pass usability objectives to adequately deliver CPAP treatment.

Inclusion Criteria:

• Participants willing to give 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 currently using a ResMed nasal pillows mask

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 established on a ResMed nasal pillows mask