This document applies to masks and their accessories used to connect sleep apnoea breathing therapy equipment to the patient. It specifies requirements for masks and accessories, including any connecting element, that are required to connect the patient-connection port of sleep apnoea breathing therapy equipment to a patient for the application of sleep apnoea breathing therapy (e.g. nasal masks, exhaust ports and headgear). Sleep apnoea breathing therapy equipment is covered by ISO 80601-2-70. Figure A.1 shows the typical elements of this document together with the sleep apnoea breathing therapy equipment of ISO 80601-2-70 that form a sleep apnoea breathing system. This document does not cover oral appliances. NOTE This document has been prepared to address the relevant essential principles[8] and labelling[9] principles guidances of the International Medical Devices Regulators Forum (IMDRF) as indicated in Annex BB.