35mm Thin. These things sound GREAT and can get really really loud. They don't have much bass at all so make sure you use it with a subwoofer. The center channel sounds great. Make sure to get the larger 301 instead of the 101 for the center as it comes with the bottom bookshelf mounting holes.

Looks fantastic and sounds fantastic!!

One of the few products on the market to wall mount under a flat panel tv. Amazing quality sound when even compared to the full size centre it replaced. Amazing quality sound from a speaker a little over an inch deep. Not cheap but worth the money.