Main control IC: AC 6921 Bluetooth IC: AC 6921 Bluetooth version is 5.0 Music format: MP3 or WMA or WAV or FLAC or APE lossless format Bluetooth calling function recording function Folder switching function Radio FM frequency: 87.5-107.5 MHZ Support function introduction: support MP3 or USB or TF or LINE IN or FM or BLUETOOTH or remote control connection or DC 12V Button and interface function 1. PREV: Twist to the left to select the previous song : Twist right to select the song 2. IR: infrared receiving module 3, MIC: support call and recording functions 4. USB interface: connect U disk (maximum support 32GB) 5. LCD screen: synchronous display of lyrics 6. SD card slot: connect SD memory card (maximum support 32GB) 7. AUX interface: audio input interface 8. Volume knob: control the volume 9. REC: Press and hold the REC button to start recording, press the REC button again to cancel the recording function and play the recorded file when recording, you need to connect a storage device, such as a U disk or TF card 10. REPEAT: Press the single loop function once, press it again to cancel the single loop, and play it in sequence 11. -: The short key is to switch to the previous folder, and the long press is to rewind 12. and: Short key is to switch to the folder, long press is fast forward 13. PLAY or PAUSE: Short press is to switch between pause and play long press is to radio FM automatic station 14. MODE: Switch between USB or TF or FM or AUX or BLUETOOTH Material: plastic colour: black Package Contents: 1 x decoder board 1 x remote control 4 x lines Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.