Car speakers or a portable radio can be used. They tell you what radio station to use to get the sound for the movie you ate watching. It is a FM station.
If your car has bluetooth and your have a speaker thats bluetooth. My kids just bought a adapter that plugs into the car charger they bought a small boombox so they can hear while sitting outside the car.
Anything that receives an fm signal can be used. No app.
No app just FM radio frequency
Car
Car speaker
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