This device is a dbx SR-328 Power Sequencer / Power Conditioner System (commonly produced/branded as a rackmount 8-channel sequence power controller).
Key Features & Functionality:
Power Sequencing: Automates turning equipment on and off in a timed sequence across channels (CH1–CH8) to prevent electrical surges, high inrush currents, and loud speaker "pops."
Front Outlets & Display: Features front-panel bypass outlets, LED channel status indicators, a digital voltage readout display, an air circuit breaker switch, and an aux/USB power port.
Rear Outlets: Houses 8 multi-standard universal AC power outlets on the back panel for rack-mounted audio gear (amplifiers, mixers, processors).
Form Factor: Standard 1U 19-inch rackmount chassis designed for pro audio racks, DJ setups, and live sound systems.