Yamaha's digital mixer, the O3D. I have confirmed its basic operations for this listing. I have confirmed the following operations: * Sound output confirmed by connecting sound sources to analog inputs from 1ch to 16ch, normal operation of input trimming knobs for each channel, normal operation of faders and panning for each channel. * Normal operation of the jog dial (confirmed no malfunctions in the reverse direction). * Normal operation of moving faders during scene recall, etc. * Normal operation of peak indicators (LEDs). * Normal operation of patch buttons. * Output from the headphone output. * Display on the LCD screen. * Normal operation of the effector section (parameter adjustment). I own various digital devices from this era, and based on the above confirmations, I believe that there are generally no malfunctions. It is not realistic to confirm the operation of all functions, so please understand that this is a normally functioning product, including this point. Adat option card included. My impression after operating it for the first time in a while is that it is a well-made digital device. The effects section is also of high quality and is still perfectly usable, with detailed reverb, etc. Also, the moving faders have a wide range of applications and can be used as physical controllers for parameters of various software and hardware via MIDI connection. Furthermore, the sound output itself is not outdated (as was often said at the time). Please refer to the following link for detailed functions and the instruction manual: [https://jp.yamaha.com/files/download/other\_assets/4/322974/03D\_J.pdf](https://jp.yamaha.com/files/download/other_assets/4/322974/03D_J.pdf) Instant purchase OK.