For sale is a like-new condition Dayton Blower Fan. Model number is 4C668C.
Two of these were installed in my home to exhaust the fumes from making glass beads. The one for sale was only used to test that it worked but it was never used during production. The one that was used is going to be installed to exhaust the fumes and steam from my homebrew rig.
It comes with the two mounts (already attached). There is an adapter for the intake to fit a seven-inch round duct that can easily be removed or re-sized with another adapter. Also, I have a home-rigged adapter for the output that converts the square out into an eight-inch round duct (not pictured). I wired 14-gauge romex to it. You can either hard-wire it to your home electrical system or install a male plug on the end.
Price is firm at $180 (can be ordered from Sears for $286 brand new)
UPS or FedEx shipping is an option at your expense. I work in St. Paul, MN and live about 40 miles north of there so if you're local, feel free to pick it up!