Replacement tub for the H4i Humidair Humidifier, used on S8 machines. It has a rounded triangular metal plate in the bottom of the tub.
The Humidair 4i is an optional upgrade for ResMed S8 CPAP, Autoset Spirit and Autoscore flow generators. The H4i clips onto the front of the S8, replacing the front sound baffle.
Make sure your Humidifier is an H4i before you order this replacement tub.