A kind of special speaker, but there is no sound device inside. It depends on a high-technical crystal to shake any hard surface, like wood, glass, wall, stone and so on, and make hard surface send out the music. 

Attractive function:                                                                                                                   wireless;
build-in MP3 with 2GB memory;
build-in battery,chargable with USB wire;
cupul help fix it on the glazed surface;
power on/off button;
pause/play switch,LED light button,can shine;
volume control buttom;
songs switch button.