"1. Bluetooth specification: Bluetooth V4.2 JL 2. L.W.H.: 90*35*35 mm, weight: 38g 3.Supply voltage: 12V-24V, USB output: 5V / 2.4A 4.FM frequency: 87.5-108MHZ 5.Support USB playback (32G MAX), support format: MP3, WMA 6. After connection to phone Bluetooth, tune up an empty channel on the car FM, and then tune up the same empty channel on the Bluetooth transmitter, this way you can connect"