An apparatus for delivering humidified gases has a connection manifold (8) adapted to connect with inlet (5) and outlet (6) ports of a slide-on water chamber (2) in a single slide on motion. Connection of the gases inlet (5) and gases outlet (6) ports as well as any additional electrical and/or pneumatic connections are all made in the same slide on motion. The water chamber (2) may include inwardly extending elongate extension tubes (30,31) and at least one of the extension tubes may also have an air bleed aperture (33) to aid filling of the chamber (2).
