Unknown Generic MP3 format Audio Player U Disk TF Card Amplifier Decoder Board Module 1. Onboard 2W mono amplifier (5V power of up to 3W) is directly connected to the speaker (recommendation 4 3W speakers), 3.5mm gold plated headphone jack can connect with headphones or external audio.  2. With a MicroUSB port, through the mobile phone data line can use mobile power supply or the USB cable to charge the MP3 battery, also can use 3.7V lithium battery,or USB 5V power supply.  3. Support TF Card (mobile phone memory card) and U disk play mode.  4. No soldering with speaker terminals for easy wiring.  5. The module is designed to facilitate modification.  6. Power range: 3.7~5.5V.  7. Product size: 45mm*36mm. Key Operating Instructions:  "P / P / Mode" button: "Press" for the "Play/Pause" Switch, "long press" for U disk, TF card mode  "Repeat" button: "Press" for single/all song" mode (no long press)