The item pictured is a dbx 231 2-Series Graphic EQ. It is a dual-channel, 31-band equalizer designed for professional audio applications.
It features two 31-band, 1/3-octave constant Q frequency bands.
Switchable boost/cut ranges of ±6 dB or ±12 dB.
Includes a 12dB per octave 50Hz low-cut filter.
Provides XLR and TRS inputs and outputs