The invention relates to a nasal cannula (30, 70) comprising an inlet tube (71) adapted to, in use, be in fluid communication with a pressurised source of gases,a pair of nasal prongs (40, 41； 72, 73) arranged in fluid communication with the inlet tube (71), the prongs adapted to, in use, to communicate gases from the inlet to the nares of a patient, a body section (30, 70), the prongs (40, 41； 70, 71) attached to the body section (44, 75),a head strap (75), the body section (30, 70) and the prongs are maintained against the patient's face by way of the headstrap (75), wherein, in use, the prongs are non-sealing with the nares of a patient.
