Tom Gardner fired this volley in news:mnb0uq$8lv$1
@speranza.aioe.org:

Is anybody familiar with this brand? I would like three; a 14" in the
kitchen and a 10" in each of two bathrooms. Any down side?

Oh... there IS a major downside I forgot about.

Any "roof penetrating" modification is best installed at construction
time or during re-roofing. INEVITABLY, a retro-fit on an existing roof
will end up leaking, because nobody is willing to 'weave' shingles
anymore.

If the job were _really_ done right, it would be just as good on an
existing roof as on a new one. But that just never happens anymore in
today's G.A.S. construction trade.

Lloyd