ART MDC-2001 Master Dynamics controller.
Full analog stereo dynamics processor with a compressor, de-esser, expander, noise gate, exciter, and peak limiter/clipper.
A lot of function in one box.
It has been repaired once, but is fully functional.
Blue tape on the back is to remind user the xlr outputs are balanced only and to use an adapter for best results if driving an unbalanced input.