Universal RCA. As far as Tony's point about the loudness of it, he's probably right. But my 2001 Ram is a diesel, and one with very little muffler at that, and it goes plenty loud for me. I did have to turn the gain all the way up on the OEM-1 though. Sure is a slick installation though.. Took me 15 minutes to replace the empeg with the original head unit a couple days ago so it's ready to trade in, and since it's all plug and play, no one could ever tell I had the empeg in there..