CRUST Car Bluetooth Device for Music System, FM Transmitter with QC 3.0 Dual USB Fast Charger & Call Receiver; 7 Colour LED Lights; Supports MicroSD, USB MP3 Audio Playback The Signature Acoustics ...

For example, firmware updates only work on iOS via Bluetooth, not if you plug in the receiver via USB-C (or Lightning). Also, if you connect the transmitter directly to a phone via Bluetooth ...