1.LED: dial color display, showing red, 4 colors;2.IR: infrared receiving module;3.MODE: Switching of USB / TF / FM / AUX / BLUETOOTH;4.SCAN: short pre is the switch between pause and play; short pre auto search in the radio state;5.USB: Connect USB f drive (maximum support 32GB)6.TF: Connect TF memory card (maximum support 32GB)7.AUX: audio input interface8.VOL-: Short pre is to select the previous song; pre is to decrease the volume9.VOL+: Short pre is to select the song; pre is to increase the volumeSpecifications:Colour: Blackmaterial: plasticMaster IC: Jerry 6926Bluetooth IC: Jerry 6926 Bluetooth version is 5.0 version compatible with 2.1 version, version 3.0Music format: MP3 / WMA / WAV / FLAC / APE lole music formadio FM frequency: 87.5-107.5 MHZSupport function introduction: support MP3/USB/TF/LINE IN/FM/BLUETOOTH/e Control/ DC 5V or 12V (optional)About the structure: panel size:92 * 41MM,the depth of the board is 21MMPackage contents:1 * Bluetooth MP3 board1 * e control (Not Bring the Battery)Only the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the ture a little different from the real thing. The measurement allowed error is +/- 1-3cm.