1. The microUSB power supply interface allows power to be supplied via a mobile power adapter or USB charger using the phone's data cable. It can also use a 3.7V lithium battery and a USB 5V power adapter. 2. sound quality, builtin 2W mono amplifier (up to 3W with 5V power supply), directly connected to the speaker (recommended with a 4ohm, 3W speaker). Goldplated 3.5mm headphone jack can be connected to headphones or external audio devices. 3. Product description: Supports MP3 format, autoplay on poweron, red LED indicator updates during playback. Supports Udisk playback mode (tested with 32G), TF card mode (tested with 16G). Defaults to TF card mode on startup; if no TF card is detected, it automatically switches to Udisk mode. If both devices are installed, the playback mode can be manually set. Refer to the main user manual for details. 4. Supports TF card (mobile memory card) and Udisk playback modes. No soldering required for horn terminals, making wiring convenient. Modular design allows for easy modifications.