Inline Duct Fan Adapter (6")

This is an adapter cone set that I made to replace an inline duct fan (squirrel cage type) in a shower exhaust for one of our bathrooms.
The original was a wimpy and very noisy blade type fan that was part of a ceiling light fixture.
It had a motor using sleeve bearings and after a very few years the bearings made about as much noise as the fan blades.
Worse, they could not be effectively lubricated (believe me, I tried).
So I purchased and installed an inline "remote" squirrel cage blower some years ago.
However, even it was not all that quiet and only moved around 150 cfm of air, which was barely adequate.

Recently I was sorting through some things and came across an old NMB 5915PC-12T-B30 pancake blower I had forgotten I had.
It is, under ideal conditions, rated at around 240 cfm, a considerable improvement.
It is also MUCH quieter than the blower it eventually replaced.
You can still purchase fans like these on Amazon and other places for around $40USD.
There are 240 vo