The original Apollo x6 is the Thunderbolt interface a lot of studios used as the front of the room once they started trusting UAD for the monitoring and the printing. Unison preamps are the reason. They load the microphone the way the preamp you are modeling loaded it, so a 1073 or a 610 plug-in on the way in is not just an EQ curve after a clean pre. The rest of the box is straightforward: enough analog I/O to run a small studio, onboard UAD processing so the plug-ins do not have to live on the computer, and the talkback and monitor control people got used to. This is that first-generation x6. The face is the original, not the later Gen 2. Plug-in licenses sit on a UA account and may not come with the hardware, so the sale is the interface. Smoke-free studio. It works. The 500-series modules in the rack photo are listed separately.