A humidification chamber (400) for humidifying gases, comprising: a water tub (452) that is configured to receive a volume of water, the water tub comprising a base surface (470) having a heater plate (494)； a lid (456) hingedly coupled to the water tub (452) for enclosing the water tub (452) to define the interior volume of the humidification chamber (400) and which is movable between a closed position in which the water tub (452) is closed by the lid (456) and an open position in which the water tub (452) is open； at least one operable clip (190) provided on either the lid (456) or water tub (452) which is configured to engage with a complementary catch (190) provided on the other of the water tub (452) or lid (456), for securing the lid (456) in the closed position； a gases inlet (140) for receiving a flow of gases into the interior volume of the humidification chamber (400), the gases inlet (140) having an associated inlet conduit (142) extending into the interior volume of humidification chamber (400)； and a gases outlet (150) through which a humidified flow of gases may exit the interior volume of the humidification chamber (400), the gases outlet (150) having an associated outlet conduit (152) extending into the interior volume of the humidification chamber (400).
