Product review (5 stars): The bird screen is very sturdy. I used expanding foam and OSI Quad to ...
Worked as intended.  We used for the wall of our house when we re-did our kitchen and needed a louvered vent for the 10" duct we had coming out the side.

Make sure you use washers when mounting the cap.

Also, when mounting, any flex one way or the other could cause the louvers to bind and not shut all the way. Keep a close eye when mounting to make sure you don't do this.

The bird screen is very sturdy.  I used expanding foam and OSI Quad to fill int he gaps and seal the rest of the spots.