Super sound quality, onboard 2W mono amplifier (5V supply up to 3W) directly connected to the speaker (recommended with 4 ohm 3W speaker), 3.5mm gold-plated headphone can be connected to headphones or external audio. With -USB supply interface, it can be powered by mobile supply or USB charger through the mobile phone data cable. It can also 3.7V lithium battery and USB 5V supply. Support TF card (mobile phone card), U disk playback mode;There is no need for welding with horn terminal, which is convenient for wiring;Modular design is easy to modify. product description:1. Support MP3 , auto play when on, red LED indicator is updated when playing;2. Support U disk (tested 32G), TF card (tested 16G) playback mode; on default TF card mode, if there is no TF card automatically jump to U disk mode, and both devices are installed, you can manually Set the playback mode, please refer to the key operation instructions for details. 3. The buttons can adjust the up and track switching, volume +-, pause / play, mode switching, please see the button operation instructions for details;4. You can press the button to set the "single / full song" cycle, the default is the full song cycle at -on, press the "Repeat" key to change the cycle mode Key operation instructions "Prev / V--" key: "Short press" is to switch "previous" song, "long press" is "decreasing volume" " / v ++" key: "Short press" is to switch "" song, "Long press" is "Volume increasing" "P / P / Mode" key: "Short press" for "play / pause" switch, "long press" for U disk, TF card "mode" "Repeat" key: "Short press", for "single / full song" cycle switching (no long press function) Product specifications supply range: 3.7 ~ 5.5V Exquisite double-layer board design, large area copper plating, stable and reliable. colour: blue Material: PCB size: 45 * 36mm Package Contents: 1 * mp3 decoding module Note: 1. "Long press" time is about 2S 2. If you U disk mode, 5V supply is recommended, some U disks do not support 3.7V supply. Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.