Yeah, I mean I figured out that it was a metal bumper when it said it was an aluminum bumper on their webpage and in the title on Amazon. 😛
But I think we'll have to see how it degrades the signal. I used an Element Case Vapor Pro on my 4S and had no signal issues. It also looks like this one is lined with a TPU material so the aluminum doesn't come into contact with the metal band. I also wonder though how you put it on... 😕