Crutchfield Customer Review (What's this?)
Purchased these to protect the Polk speakers I purchased at the same time. No instructions for how to install with the speaker. Hopefully I got it right. Speaker is a snug fit in the opening with this behind it. Time will tell if it keeps the elements out of the back of the speaker.
Pros: Good idea to protect speakers from the elements. Dust especially, in this area.
Cons: A little instruction would be a plus.