A gases conduit (3) for use as part of a breathing circuit which delivers heated, humidified gases to a patient for medical purposes, has a first end adapted for connection to an outlet (4) of a humidifier chamber (5), and a second, patient end adapted for connection to a patient interface (12). Said gases conduit and/or said patient interface include an RFID tag (12) adapted to sense a parameter of gases passing through said gases conduit. In the gases conduit, the RFID tag is located at or close to said second, patient end. The gases conduit is a breathing conduit with an integral heater wire (11), said heater wire being dual-configured to provide heat to an inside surface of said breathing conduit, and also to act as an aerial for the RFID tag.
