I asked for this info a while ago and no one seemed to know much. It should be an eight incher. I contacted POLK and they said they were working on a solution and to check back with them. I have and it looks to be a 2008 item with them. JL might have something. I just wanted the dimensions of the enclosure but I have nothing to offer in that arena. Crutchfield is not much help either. Good Luck!!