For more than three decades, type III devices have been used in the diagnosis of sleep disordered breathing in supervised as well as unsupervised settings. They have satisfactory positive and negative predictive values for detecting obstructive and central sleep apnoea in populations with moderately high pre-test probability of symptoms associated with these events. However, standardisation of commercially available type III devices has never been undertaken and the technical specifications can vary widely. None have been subjected to the same rigorous processes as most other diagnostic modalities in the medical field. Although type III devices do not include acquisition of electroencephalographic signals overnight, the minimum number of physical sensors required to allow for respiratory event scoring using standards outlined by the American Academy of Sleep Medicine remains debatable. This technical standard summarises data on type III studies published since 2007 from multiple perspectives in both adult and paediatric sleep practice. Most importantly, it aims to provide a framework for considering current type III device limitations in the diagnosis of sleep disordered breathing while raising research- and practice-related questions aimed at improving our use of these devices in the present and future., Competing Interests: Conflict of interest: T. Penzel reports personal speaker fees from Cerebra, Jazz Pharma, Löwenstein Medical, National Sleep Foundation and Neuwirth; consulting fees from Bayer Healthcare and Cerebra; travel support from Jazz Pharma and Nukute; participation on advisory boards for Nukute and Cerebra; stock or stock options with The Siestagroup, Nukute and Advanced Sleep Research; receipt of equipment from Neurovirtual; institutional fees and research grants from Bayer Healthcare, Cidelec, Löwenstein Medical, Novartis and Springer Publisher. T. Penzel also reports the following leadership roles: German Sleep Society (president, unpaid), IEEE Engineering in Medicine and Biology (advisory committee member, unpaid), German Society on Biomedical Engineering (board member, unpaid), DIN – German standardization body (committee member, unpaid). W. Randerath reports institutional fees, research grants and speaking fees from Philips Respironics, Heinen & Löwenstein, Jazz Pharmaceuticals, Weinmann, Resmed, Inspire, Vanda Pharma and Bioprojet, and is head of European Respiratory Society assembly 4 (Sleep Disordered Breathing). R.L. Riha reports one-off personal speaker fees and participation on an advisory board from Jazz Pharmaceuticals, and is also co-director of Sleep Consultancy Ltd. D. Testelmans reports institutional fees and educational grants from AirLiquide, Philips Respironics and Resmed. J. Verbraecken reports institutional fees and educational grants from Accuramed, Agfa-Gevaert, AirLiquide, AstraZeneca, Bekaert Deslee Academy, Bioprojet, Desitin, Ectosense, Fisher & Paykel, Heinen & Löwenstein, Idorsia, Inspire, Jazz Pharmaceutics, Medidis, Mediq Tefa, MSD, NightBalance, OSA Academy, OSG, Oxford Pharmagenesis, Philips Respironics, ResMed, Sanofi, SomnoMed, Springer, Total Care, UCB Pharma, Vivisol, Wave Medical and Westfalen Medical; consulting fees from Vermedia; and reports the following leadership roles: president (up to August 2021) and past president of the Belgian Association for Sleep research and Sleep medicine (since September 2021). M. Celmina reports lecture honoraria from Rare Diseases Conference and Latvian Medical Association; support to attend various conferences (IPSA, Baltic Sleep Meeting, Nordic Sleep Meeting) provided by Children's Clinical University Hospital (Riga, Latvia); and is a member of the board of the Latvian Sleep Medicine Society. A. Morley reports lecture honoraria from Sleep Consultancy Ltd and Sleep Scotland; participation on advisory board for the BTS Guideline for Pediatric Sleep Disorders; and is a board member of Association of Respiratory Technology and Physiology – Sleep. L. Roberti reports grants/funding to AAI ETS patient organisations from Resmed, Fisher & Paykel, Jazz Ph, Bioprojet, Vitalaire, Linde, Medicair, Philips, Olympus, Respiraire and Vivisol; and also reports the following leadership roles: President of Associazione Apnoici Italiani ETS (Italian Sleep Apnoea Patient Association), Sleep Apnoea Patient Representative of EMA, and Member of ELF Sleep Apnoea PAG. W. Ruehland reports travel support from Institute for Breathing and Sleep to attend Sleep Downunder and TSANZSRS Conferences, and from Australian and New Zealand Sleep Science Association to attend Sleep Downunder conference; and also reports the following leadership roles: board member of the Australian and New Zealand Sleep Science Association, committee member of the Medical and Scientific Research Committee, Institute for Breathing and Sleep, and is director of Respiratory Quality Assurance Pty Ltd, which provides PSG scoring external proficiency testing program (QSleep) for sleep centres. G. Grundström is Chairman of the Swedish Sleep Apnea Association. B. Cooper, R. Hamutcu-Ersu, A. Kaditis, A. Pataka and A. van Eyck have no conflict of interest to disclose related to the topic discussed in this technical standard., (Copyright ©The authors 2023. For reproduction rights and permissions contact permissions@ersnet.org.)