In an embodiment, a connector or connector assembly for attaching a nasal cannula with a gas delivery hose includes a sensor port for a sensor probe positioned near an end of a nasal cannula, which can allow the sensor probe to be placed closer to the patient's nostrils than previous connector parts allowed. The connector can be configured to advantageously allow the nasal cannula to rotate relative to the gas delivery hose, thereby allowing a patient or healthcare provider to untangle or otherwise straighten the hose or the cannula. The connector assembly can be configured to automatically align locking protrusions on a first component with locking recesses on a second component, where insertion of the second component within the first component causes the second component to rotate relative to the first component, thereby aligning the locking protrusions with associated locking recesses.