6" Backdraft damper - prevents drafts from coming back into your home. Usually used with Clothes dryers
This was originally packed with a kitchen vent or dryer - I forget

Signs of storage but it's clean and operated properly
Two spring loaded flaps
WAS NEVER INSTALLED - LAYING AROUND FOR A WHILE - ONE OF THE SPOKES IS SNAPPED AS SHOWN IN PICTURES - Doesn't really affect the performance the ring is still enough with the plastic sleeve that is attached ( Black Part) - so make your offer with that in mind.

Male female insertion.




Note on my shipping practices - please read.

All items are plus shipping with certain exceptions when I can off free or flat rate shipping.
There is a large disparity between shipping companies and the area and service level.
For that reason I accurately measure and weigh the item as packed.
Size matters so I estimate a minimal sized package yet offer full adequate protection for your item. Please explore all options at "more details" link on the listing. 
Shipping is same or next day regardless of what is stated in "details".