This is an attache case-style analog mixer from SONY. While the faders have overall scratchiness, I have confirmed the operation of all microphone input channels and the echo. The echo has an analog delay-like feel, typical of the era, with the TIME adjustable in 3 steps via a switch, and fixed feedback. The pan also has a 3-step switch. The VU meters also work. The sponge in the battery compartment lid has deteriorated, and I do not recommend using batteries in this condition. Although a power supply is not included, it operated with a 12V, 2.1mm, center-negative DC adapter. Despite its issues, I think it's an interesting item. Please purchase only if you understand that there is scratchiness, no power supply is included, the sponge has deteriorated, and it is an old item.