A mask mounting mechanism for use in connection with a patient interface device including an extension member with a first end and a second end, wherein the first end is attached to a portion of the mask, and the second end extends from and is spacially separated from the mask. The semiconductor substrate comprises first and second wafers which are directly bonded together along a bond interface. Inlets of catalyst units are connected to outlets of the first exhaust pipes, and second exhaust pipes are connected to outlets of the catalyst units. , at a \u201c10 foot\u201d interaction level.