simple wall plate
Crutchfield Customer Review (What's this?)
It's the same wall plate you would get elsewhere, exactly... so check locally and save a few bucks. I only purchased it here because i wasn't sure if the hole was the same size as a normal wall plate for my purpose with the On-Q straps.
Pros: Needed for a nice installation. does exactly what it's supposed to do.
Cons: Pricey compared to the local big box hardware store.