This is a prospective, unblinded, open-label, single group study. All subjects will undergo concurrent screener app, HSAT testing, and in-lab polysomnography.

Inclusion Criteria:

• Participant is 18 years of age or older
• Participant is willing to provide informed consent
• Participant is willing to participate in all study related procedures

Exclusion Criteria:

• Unable to cease PAP therapy during PSG (if currently using)
• Requires use of oxygen therapy during sleep
• Diagnosis of untreated clinically relevant sleep disorder (other than SDB)
• Pregnant
• Participant is unsuitable to participate in the study in the opinion of the investigator
• Participant has a permanent pacemaker, sustained non-sinus cardiac arrhythmias, and/or takes alpha blocker or short acting nitrate medication.