The speaker is magnetic and can be easily attached to the roof of a car. It draws power from a socket, so there's no troublesome wiring. Music is played via a micro SD card. Everything except the megaphone is new and unused. However, the instructions are in Chinese. Although it's new, the operation hasn't been confirmed. I've used the same set before. The connection is quite easy. I used to play music and do mobile sales with my car. Thank you.