The Yamaha SV-150's electronics are contained in an external control box, which functions as a digital tuner, metronome, and effects processor with 24 digital sounds (plus a "clean" channel, with no effects). The unit also reads tunes from an included SD card reader that can play .wav, .mp3, and MIDI files for you to play along with -- comes pre-loaded with some basic tunes. You can also slow down (up to 50%) or speed up (up to 150%) the tunes you're playing along with, without altering the pitch -- regardless of their file format!
It's important to note that the SV-150 cannot be played in any amplified situation without its dedicated control box. Even with an adapter cable, you won't get any sound if you plug the SV-150 directly into an amplifier, a mixing board, or an effects processor, instead of the Yamaha control box that comes with the instrument. Plugging headphones directly into the SV-150 won't work, either -- It's not possible to bypass the violin's control box.
The Yamaha SV-150 may well be the perfect instrument for silent practice, but not offering an output cable and designing the control module so that the only available output is via a 1/8" line out means that players who want to perform with this instrument will have to purchase a separate 1/8" to 1/4" male-to-male adapter cable.
Comes in a heavy corrugated shipping box, and includes the instrument, control box, and earbud headphones.