Hey Enigma,
I think you need to post in the Airway Clearance thread at the top of this section to get an answer from Dr. Zanni. I use the frequencer, however, and have found it to be super effective. I did a much more comprehensive review of it here on my personal blog:
<a target=_blank class=ftalternatingbarlinklarge href="http://amatteroflifeandbreath.blogspot.com/2009/10/rockin-out-and-coughin-out.html
">http://amatteroflifeandbreath....-and-coughin-out.html
</a>
I really love this machine. I have tried a number of airway clearance techniques and always found them helpful in some way or another, but this is the best I've found for me personally. I encourage you to talk to your doc and check it out.
Piper