This is a Bluetooth add-on unit for Toyota genuine multi-nav systems (20-pin). Compatible vehicles: 17 Majesta - Installation confirmed with CD changer only 17 Crown - Installation confirmed with CD changer only 30 Celso - Mark Levinson compatible 18 Crown - Mark Levinson compatible 18 Majesta - Mark Levinson compatible IS250 Early Model - Mark Levinson compatible IS350 Early Model - Mark Levinson compatible LS460 Early Model - Mark Levinson compatible LS600h Early Model - Mark Levinson compatible and others. It is believed to be compatible with Toyota genuine multi-nav systems with a 20-pin connector (see photo 2). Tools required for installation: Trim removal tool 10mm socket Phillips head screwdriver Installation method: For the 30 Celso, simply remove the changer unit and insert the included 20-pin coupler between the removed coupler and the changer unit. There is no need to add troublesome ACC or BAT wiring. Even with this unit installed, CDs can be used as usual. My experience using it: I loved my Celso, but the inability to use music streaming services like YouTube Music and Spotify was a problem. I considered installing an aftermarket navigation system, but I had various desires, such as not wanting to change the original interior. However, by using this item, all the problems were solved, and I am very satisfied.