Main control IC: AC6921 Bluetooth IC: AC6921 Bluetooth version is 5.0 Music format: MP3 / WMA / WAV / FLAC / APE lossless format Bluetooth call function Recording function Folder switching function Radio FM frequency: 87.5-107.5 MHZ Support function introduction: support MP3 / USB / TF / LINE IN / FM / BLUETOOTH / remote control connection / DC 12V About the structure: Panel size: length 112 * width 62 MM, the panel is surrounded by screw holes, and the depth of the panel is 22MM 1. Buttons and interface functions 1. IR: infrared receiver module; 2. MIC: Support call and recording function; 3. USB interface: connect to U disk (maximum support 32GB); 4. LCD screen: synchronized lyrics display; 5. SD card slot: connect to SD memory card (maximum support 32GB); 6. AUX interface: audio input interface; 7. Volume knob: control the volume; 8. REC: Long press the REC button to start recording, press the REC button again to cancel the recording function and play the recording file; when recording, it is more necessary to connect a storage device, such as a U disk or TF card; 9. REPEAT: Press the single cycle function once, and press it again to cancel the single cycle and play in sequence; 10. PREV/: Short press is to select the previous song; long press is to rewind; 11. PLAY/PAUSE: Short press is to switch between pause and play; long press is to radio FM automatic station; 12. NEXT: Short press is to select the next song; long press is to fast forward; 13. MODE: Switch between USB / TF / FM / AUX / BLUETOOTH;