I was cleaning my house and found this. I'm not an expert, so I don't know what it's for. Therefore, I haven't checked if it works. If you know more about it, please take a look. BOSE power amplifier, a multi-functional model with level and microphone adjustments. - Brand: BOSE - Model: Power Amplifier - Connection Terminals: XLR, RCA - Adjustment Knobs: Level adjustment knob, microphone adjustment knob - Power Switch: Power switch This is a used item, so no claims and no returns are accepted. Thank you for looking.