Medical apparatus, namely, continuous positive airway pressure (CPAP) devices; breathing masks for medical purposes; CPAP breathing masks for medical purposes; Oxygen masks for medical use; Oxygen masks for medical purposes; patient breathing system comprising a breathing circuit and connections to patient; Oxygen concentrators for medical use; oxygen concentrators for use by patients suffering from chronic obstructive pulmonary disease (COPD) and other respiratory disorders; oxygen monitors for medical use; nasal interfaces for medical purposes; medical tubing connectors; parts and fittings for the aforementioned goods