An apparatus for use in humidified gases delivery treatment comprising: a housing, a pressurised gases supply within said housing, a pressurised gases outlet in said housing in fluid connection with said pressurised gases supply and adapted to make fluid connection with an inlet of a heatable water chamber in order to provide gases flow to said chamber, a humidified gases return in said housing, adapted to make fluid connection with an outlet of said chamber in order to receive humidified gases from said chamber, a chamber heating means connected to said housing and, said housing includes a humidifier engagement (17, 19) locating said chamber adjacent said chamber heating means, said chamber heating means adapted to vaporise liquid water in said water chamber in order to provide water vapour to said gases flow passing through said water chamber, a patient outlet in said housing, in fluid connection with said humidified gases return in order to receive humidified gases from said humidified gases return and provide humidified gases to said patient outlet, said patient outlet being in fluid connection with or adapted to make fluid connection with a breathing conduit for delivery of humidified gases to a patient, and wherein said water chamber has a base, and said chamber is engagable with said humidifier engagement (17, 19) via a single motion of engagement, and said single motion of engagement urges the base of said chamber adjacent and in contact with said chamber heating means and makes a first fluid connection between said pressurised gases outlet and said chamber inlet, and makes a second fluid connection between said humidified gases return and said chamber outlet, with said first and second fluid connections being made in the direction of said single motion of engagement. a housing, a pressurised gases supply within said housing, a pressurised gases outlet in said housing in fluid connection with said pressurised gases supply and adapted to make fluid connection with an inlet of a heatable water chamber in order to provide gases flow to said chamber, a humidified gases return in said housing, adapted to make fluid connection with an outlet of said chamber in order to receive humidified gases from said chamber, a chamber heating means connected to said housing and, said housing includes a humidifier engagement (17, 19) locating said chamber adjacent said chamber heating means, said chamber heating means adapted to vaporise liquid water in said water chamber in order to provide water vapour to said gases flow passing through said water chamber, a patient outlet in said housing, in fluid connection with said humidified gases return in order to receive humidified gases from said humidified gases return and provide humidified gases to said patient outlet, said patient outlet being in fluid connection with or adapted to make fluid connection with a breathing conduit for delivery of humidified gases to a patient, and wherein said water chamber has a base, and said chamber is engagable with said humidifier engagement (17, 19) via a single motion of engagement, and said single motion of engagement urges the base of said chamber adjacent and in contact with said chamber heating means and makes a first fluid connection between said pressurised gases outlet and said chamber inlet, and makes a second fluid connection between said humidified gases return and said chamber outlet, with said first and second fluid connections being made in the direction of said single motion of engagement.