Super sound quality, built-in 2W mono amplifier (5V power up to 3W) directly connected to the speaker (recommended with 4 ohm 3W speaker), 3.5mm gold-plated headphones can be connected to headphones or external audio. With USB power, it can be powered by mobile power or USB charger via mobile phone data cable. It can also use 3.7V lithium battery and USB 5V power supply. Supports TF card (mobile phone memory card), U-disk playback mode; No welding required for horn terminals, convenient for wiring; Modular design is easy to use. Product 1. Supports MP3, automatic playback when power is on, red LED indicator updates when playing; 2. Supports U-disk (tested 32G), TF card (tested 16G) playback mode; Power on default mode is TF card, if there is no TF card, it will automatically jump to U-disk mode, and if both devices are installed, you can set the playback mode manually, please refer to the key instructions for details. 3. Buttons can adjust track switching up and down, volume +-, pause/play, mode switching, please refer to the button operation instructions for details; 4. You can press the button to set "single/all song", the default is all songs at startup, press the "Repeat" key to change the mode. Key Operation Instructions "Prev / V--" Key: "Short press" is to switch to the "previous" song, "long press" is "volume decreasing". " / v ++" Key: "Short press" is to switch to the "next" 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" to switch "single/all song" (no long press function). Product Specifications Power Supply: 3.7~5.5V Exquisite double-layer board design, large area copper plating, stable and reliable. Color: Blue Material: PCB Size: 45 * 36 mm Package Contents: 1 * MP3 Decoding Module Note: 1. "Long press" time is about 2S. 2. If using U-disk mode, 5V power supply is recommended, U-disks do not support 3.7V power supply. Only the above package content, other products are not included. Note: Light and different screens may cause the color of the item in the picture to be slightly different from the real thing. The measurement allowed error is +/- 1-3 cm.