PhilEllis:I clearly mis-read and mis-spoke. I was thinking completely of the low pressure, constant flow adaption they offer. That is what I described, but I incorrectly called it a "positive pressure" adaption. To my knowledge, they do not offer an upgrade to make the mask maintain a positive internal pressure. Sorry and thanks.
Phil Ellis
Phil, low pressure constant flow? can you link me as I have not a clue what you are referring to?!?!