Standard H4I Humidifier Chamber for ResMed S8
Standard Humidifier Chamber for ResMed H4I. ResMed offers two humidifiers with the S8 series, the H4I and H3I. To differentiate the H4I from the H3I, the H4I does not have a logo on the front panel, rather the logo is located on the bottom. The H4I also has a larger heater plate and offers a thumb notch on the rounded top cover. The cover on the H3I is more slanted and does not offer a thumb notch.