Features: * Support signal switch directly. Support USB, TF * Support Bluetooth (Bluetooth5.0 ) (after being paired with mobile phones can realize wireless music play) * Support USB / TF / Bluetooth/FM / LINE switch. MP3 / WMA, WAV lossless music decoding chip. * Support USB / TF card switch, PREV, NEXT, fast forward, fast rewind, volume, EQ, play/pause, stop, single repeat, mute, shutdown, and direct election. * Support Bluetooth PREV, NEXT, volume, EQ, play/pause, mute, turn it off. * Support FAT16, FAT32 file system. Support for MP1 Layer3, MP2 Layer3, and MP3 Layer3 versions of the song.Support 32-320 KBPS MP3 songs. * Support power-off memory function: memory play songs and volume before power off. Rated input: 5V/500MA Power supply type: direct current (DC) 3.7~5V power supply Appearance size: 88(L)*25(H)mm Rated power consumption: USB playback current 120M Panel interface: USB, AUX Operating temperature: -20℃~60℃ Output amplitude: 600MV Key Function POWER: STANDBY ON/OFF MODE: Press this key to cycle selection and input USB→SD→BLUE→FM→LINE PREV: In the USB/SD/BT playback state, short press to select the previous song, and long press to rewind (BT is invalid in receiving In the FM state, short press to select the previous station and long press to search backward to find the station and play the current Radio AUX status is invalid NEXT: In the USB/SD/BT playback state, short press to select the next song and long press to fast forward (BT is invalid). In the FM state, a short press to select the next station Radio, AUX status is invalid VOL+: Increase the volume VOL-: Volume down REP: Enter the loop mode during USB/SD playback, short press the loop button, and enter A (full loop) →O (single loop) → FOLDER (current folder loop) → Random (random play) → NORMAL (cancel the loop function and enter the sequence play STOP: Stop playing in the USB/SD card state and press the play button to start playing other states from the first song. State is invalid MUTE: press mute in all states and press again to unmute EQ: USB/SD state is sound field mode. NORMAL→BASS→ ROCKPOP→ROCK →JAZZ→ CLASSIC→CUR PLAY PAUSE: In the USB/SD/BT playback state, short press once to pause and press again to play In the radio mode, press this button to enter the automatic search for radio stations 0~9: Directly select more than 10 numbers on USB/SD and input the number to be selected. In FM state Select the saved radio station in the mode. You can also press the number keys to directly enter the radio frequency to play the radio station Physical shooting Package includes: 1 x MP3 Decoder Board 1 x Remote Control (without battery) 1 x Installation line set or 1 x MP3 Decoder Board 1 x Remote Control (without battery) 1 x Installation line set 1 x 2x15W Power amplifier