A humidification chamber (50, 300, 400, 500) for humidifying gases, comprising: a water tub that is configured to receive a volume of water; alid (56, 456) coupled to the water tub for enclosing the water tub to define the interior volume of the humidification chamber (50, 300, 400, 500) and which is movable between a closed position in which the water tub is closed by the lid (56, 456) and an open position in which the water tub is open; the lid (56, 456) comprising a vertical flow panel that extends downwardly from the underside of the lid (56, 456) in a central region of the lid; a gases inlet for receiving a flow of gases into the interior volume of the humidification chamber (50, 300, 400, 500), wherein the gases inlet is coupled to an inlet conduit that extends between an inlet end at the gases inlet and an outlet end located at or toward an upper central region of the interior volume of the humidification chamber (50, 300, 400, 500) and adjacent a first side surface of the vertical flow panel such that the incoming gases flow enters the interior volume of the humidification chamber (50, 300, 400, 500) at that upper central region; and a gases outlet through which a humidified flow of gases may exit the interior volume of the humidification chamber (50, 300, 400, 500), wherein the gases inlet and gases outlet are provided on opposite sides of the lid (56, 456), wherein the inlet conduit extends in a substantially horizontal direction from a vertical perimeter wall of the lid (56, 456), characterised in that: the lid (56, 456) is hingedly coupled to the water tub; the humidification chamber (50, 300, 400, 500) further comprises one or more operable clips (170, 190, 200, 210, 290, 560) for securing the lid (56, 456) in the closed position; and the humidification chamber (50, 300, 400, 500) further comprises a flow director formation in the form of an inverted curved ramp surface located between the outlet end of the inlet conduit and the first side surface of the vertical flow panel, wherein the curved inverted ramp surface begins at or toward a main body portion of the lid (56, 456) at the outlet end of the inlet conduit and terminates at the first side surface of the vertical flow panel. a water tub that is configured to receive a volume of water; alid (56, 456) coupled to the water tub for enclosing the water tub to define the interior volume of the humidification chamber (50, 300, 400, 500) and which is movable between a closed position in which the water tub is closed by the lid (56, 456) and an open position in which the water tub is open; the lid (56, 456) comprising a vertical flow panel that extends downwardly from the underside of the lid (56, 456) in a central region of the lid; a gases inlet for receiving a flow of gases into the interior volume of the humidification chamber (50, 300, 400, 500), wherein the gases inlet is coupled to an inlet conduit that extends between an inlet end at the gases inlet and an outlet end located at or toward an upper central region of the interior volume of the humidification chamber (50, 300, 400, 500) and adjacent a first side surface of the vertical flow panel such that the incoming gases flow enters the interior volume of the humidification chamber (50, 300, 400, 500) at that upper central region; and a gases outlet through which a humidified flow of gases may exit the interior volume of the humidification chamber (50, 300, 400, 500), wherein the gases inlet and gases outlet are provided on opposite sides of the lid (56, 456), wherein the inlet conduit extends in a substantially horizontal direction from a vertical perimeter wall of the lid (56, 456), characterised in that: the lid (56, 456) is hingedly coupled to the water tub; the humidification chamber (50, 300, 400, 500) further comprises one or more operable clips (170, 190, 200, 210, 290, 560) for securing the lid (56, 456) in the closed position; and the humidification chamber (50, 300, 400, 500) further comprises a flow director formation in the form of an inverted curved ramp surface located between the outlet end of the inlet conduit and the first side surface of the vertical flow panel, wherein the curved inverted ramp surface begins at or toward a main body portion of the lid (56, 456) at the outlet end of the inlet conduit and terminates at the first side surface of the vertical flow panel. the lid (56, 456) is hingedly coupled to the water tub; the humidification chamber (50, 300, 400, 500) further comprises one or more operable clips (170, 190, 200, 210, 290, 560) for securing the lid (56, 456) in the closed position; and the humidification chamber (50, 300, 400, 500) further comprises a flow director formation in the form of an inverted curved ramp surface located between the outlet end of the inlet conduit and the first side surface of the vertical flow panel, wherein the curved inverted ramp surface begins at or toward a main body portion of the lid (56, 456) at the outlet end of the inlet conduit and terminates at the first side surface of the vertical flow panel.