My in-laws have a blower but I'm not sure if it is what you are referring to.
Its 2 pieces- 1 is a small fan with a manifold that connects to part #2, which is a casting of 7 pipes, curved such that their open ends stick out the top and bottom of the fireplace..like this...

edit- sorry - cant get the image to work.


It is very quiet, throws out a lot of heat, and if the fire is struggling, you can just take the fan manifold part off and use it to "fan the flames" - sometimes helps get the fire started.

As an engineer, I always wondered if we could improve such a system, but really, for the price and work involved - its well worth it.

-John

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2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)