Does what it says on the tin so to speak. Worked directly on my Suzuki Swace(Corolla clone) but had to use C adapter on brothers Corrola. Couldn't get it working on Hyundai.
You have to select Apple Play option on your car head set.
1 Plug Firestick into adapter
2 Connect 3 lead cable, C connection
to adapter
3 Connect long USB to power source, Not your head set usb
4 Connect short USB to head set, C adapter may be required