Music sequencer. All accessories are as shown in the photos. [Note] There is a faint circular mark on the screen, but it's not noticeable in the photos. I think it's hardly noticeable during operation. If you are concerned about the condition, please refrain from purchasing. - Operation has been roughly confirmed. Button responses seem to be fine. - The internal button battery has been replaced. - The screen protector has not been peeled off yet. - There is no corrosion in the battery box. The sponge shows some deterioration. If you are okay with the above information, please consider purchasing.