There are a few options. The JK RemoteMix is nice and fairly simple and the new one has bluetooth capability. We use an older one. We also have a couple of Conex FlipJacks the little one with 2 inputs and the FJ-700 with 4 inputs. My personal favorite is our good old Zercom ZMax (4 Channel) and ZMax II (2 Channel). They don't make the Zercoms anymore but you can still find them from time to time fairly cheap and you'll need a JK Daptor for the cell phone. On the the 4 Channel you also have to disable the line loss sensor. Good luck in your search!