This is a fantastic DOD R-831 31-band Graphic Equaliser. It's a straightforward bit of kit, taking in balanced or unbalanced input, applying 31-band equalisation and outputting via a balanced or unbalanced output. There's also level control for overall gain, bypass and a low cut filter.

Perfect working condition. Will accept (reasonable) offers, although it's currently the cheapest I've found anywhere else on the Internet for similar devices.

Thanks for viewing.