This is one of the simplest mp3 player module for electronics enthusiasts. Simply insert a MicroSD card, power up the board and play any song/audio. Supports mp3 format audio files. Connect a speaker and an earphone to the board and enjoy your audio. The circuit board has an inbuilt 2W mono amplifier. Features: Superior sound quality. Onboard 2W mono amplifier (5V power of up to 3W) is directly connected to the speaker (recommendation 4 Ω 3W speakers), 3.5mm gold plated headphone jack can connect with headphones or external audio. Power up the board with a Micro USB port. Use a power cable that you use to charge your mobile phone. Connect to your computer or a USB power adapter to power the module. You can also use a 3.7V lithium battery or USB 5V power supply Support TF Card (mobile phone memory card) and U disk play mode. No soldering with speaker terminals for easy connection. Power range: 3.7~5.5V Product size: 47mm x 34mm/18.50 x 13.38′ Working: Supports MP3 format, starts playing as soon as the power is applied. When mp3 is played the red LED flashes. Support U disk (tested 32G), TF Card (tested 16G) play mode; power on default TF card mode. Buttons can be used to control songs, volume up and down, pause or play, mode switching, etc. Press menu button enter the single/all song play mode.The default mode is the all song mode when powered up. Pressing the Repeat button can replace the circulating mode. Key Operating Instructions: ‘Prev / V–‘ button: ‘Press’ for switching previous song, ‘long press’ for volume down ‘Next/v++’ button: ‘Press’ for switching next song, ‘long press’ for volume up ‘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) Note: ‘Long press’ means approximately press for 2 Seconds If you use the module in U disk mode, it is recommended to use 5V power supply, some U disk does not support 3.7V power supply