This is a FIREWIRE UAD-2 Satellite Quad Custom. You need a Firewire interface on your computer to use this. This can add 4 SHARC engines to your UAD system, if you have a Firewire interface. I used it with my UAD Twin X to give me an additional 4 engines of DSP power, along with another Quad satellite. That gave me a total of 10 dsp engines to run UAD plugins. Two quads plus the 2 engines in the Twin X.
These satellites sold for $549.99.
The WHITE LED on the UAD logo doesn't come on anymore, but the unit still works just fine. For that reason, I have reduced the price to $99.00