An apparatus for humidifying a flow of breathable gas, comprising: a water reservoir including a cavity structured to hold a volume of water; a water reservoir dock structured and arranged to receive the water reservoir in an operative position; an air delivery tube configured to pass the flow of breathable gas that has been humidified in the water reservoir to a patient interface; and an intermediate component arranged for removably and non-rotatably coupling to the water reservoir dock and the air delivery tube , the intermediate component comprising retention and alignment features structured and arranged to align the intermediate component with the reservoir dock and provide a removable, non-rotatable connection with the reservoir dock , wherein the intermediate component is configured to be, in an operational configuration, both mechanically locked, and pneumatically connected, to the air delivery tube , the intermediate component comprising a tubular portion including an inlet end adapted to pneumatically connect with the water reservoir and an outlet end adapted to pneumatically connect with the air delivery tube , wherein the intermediate component comprises a resilient spring arm configured to provide a removable snap-fit connection with the water reservoir dock , wherein the intermediate component comprises a flange between the inlet end and the outlet end configured and arranged to limit insertion depth of the intermediate component into the water reservoir dock in the operational configuration by abutting a wall provided to the water reservoir dock , characterized in that the intermediate component further comprises a part-annular side wall extending around at least a portion of the outlet end and projecting outwardly from the flange along the outlet end , the outlet end and the part-annular side wall cooperating to form an annular channel for receiving the air delivery tube . a water reservoir including a cavity structured to hold a volume of water; a water reservoir dock structured and arranged to receive the water reservoir in an operative position; an air delivery tube configured to pass the flow of breathable gas that has been humidified in the water reservoir to a patient interface; and an intermediate component arranged for removably and non-rotatably coupling to the water reservoir dock and the air delivery tube , the intermediate component comprising retention and alignment features structured and arranged to align the intermediate component with the reservoir dock and provide a removable, non-rotatable connection with the reservoir dock , wherein the intermediate component is configured to be, in an operational configuration, both mechanically locked, and pneumatically connected, to the air delivery tube , the intermediate component comprising a tubular portion including an inlet end adapted to pneumatically connect with the water reservoir and an outlet end adapted to pneumatically connect with the air delivery tube , wherein the intermediate component comprises a resilient spring arm configured to provide a removable snap-fit connection with the water reservoir dock , wherein the intermediate component comprises a flange between the inlet end and the outlet end configured and arranged to limit insertion depth of the intermediate component into the water reservoir dock in the operational configuration by abutting a wall provided to the water reservoir dock , <EOS>