7inch Full HD Touchscreen Portable Wireless Car Stereo, Bluetooth Touch Radio, Apple CarPlay & Android Auto by Lieucyst

3 Ways of Sounding: FM connected to car audio: Connects to the car audio system by matching the FM frequency of the transmitter with the car stereo's FM frequency. This option provides wireless connectivity only.Built-in horn: This car stereo comes with a built-in speaker, which can be used to play audio. However, for louder sound, it can be transferred to the car's speakers.AUX connected to the car audio: This option requires connecting the AUX output of the car stereo to the AUX input of the car's audio system. Before doing so, make sure to close the FM interface.