This is the Sega Grand Pianist, worldâ€™s smallest functional â€œgrand pianoâ€.
You canâ€™t actually play a music in it by yourself, and your fingers are far wider than the 4mm keys. But with the help of something with a sharp tip, as a toothpick, youâ€™ll be able to see that all the 88 keys are functional and reproduce the correct note (actually synthesize and play through a built-in speaker)..
But you wonâ€™t need to play the tunes yourself; it comes with 100 songs preinstalled and has a SD card slot, so you can add others. While playing the songs, the keys will act accordingly (see it working in a video at the end of the post).
The price, it will cost around $415 in Japan and $549 in US.
After the jump: more images, video, specs and links.