This is a kit for listening to music on a car navigation system that doesn't support Bluetooth. It outputs music received via Bluetooth from your smartphone through the AUX (headphone jack). You can use the buttons to fast forward, rewind, pause, etc., and it can also be used for phone calls. As described in the receiver's manual, connecting the wiring and powering it from the cigarette lighter socket can sometimes cause noise in the music, so I'm also including a smof noise filter. (This eliminated the noise in my Nissan Note E12.) Please use double-sided tape to secure the receiver body to the instrument panel, etc. (The original product came with a metal plate and used magnets to attach, but it fell off easily, so I threw it away. Sorry.) I no longer need it because I sold my car. I hope someone can make good use of it.