1、AUTOMATIC PLAYBACK: This lossless decoding board supports MP3 format and automatically starts playing when powered on. The red LED indicator light updates when playing. 2、MULTIPLE PLAYBACK MODES: Mp3 module supports U disk (tested up to 32G) and memory card (tested up to 16G) playback modes. The default mode is memory card playback, and if no memory card is detected, it automatically switches to U disk mode. If both devices are installed, you can manually set the playback mode. (U disk and memory card are not included). 3、BUTTONS CONTROL: The buttons allow you to adjust the track, volume, pause, play, and mode. For detailed instructions, please refer to the button operation guide. 4、CUSTOMIZABLE LOOP MODES: You can set the loop mode to single track or full track by pressing the Repeat button. The default mode is full track loop. 5、BUILT IN AMPLIFIER: Equipped with a 2W single channel amplifier (up to 3W with 5V power supply), this board provides exceptional sound quality. It can be directly connected to a speaker (recommended to pair with a 4Ω 3W speaker) or headphones using the 3.5mm gold plated jack.