This part of the European Standard specifies requirements for masks and accessories which are required to connect the patient connection port to a sleep apnoea breathing therapy device and the mask to a patient, and are used for the application of sleep apnoea breathing therapy e.g. nasal masks, gas exhaust ports, connecting element and headgear. This part of EN ISO 17510 does not cover oral appliances. NOTE 1 Sleep apnoea breathing therapy devices are covered by EN ISO 17510-1 (see Figure A.1 for typical elements of the two parts of EN ISO 17510). NOTE 2 Annex A contains rationale statements for this Part of EN ISO 17510.