1. Supports TF card (memory card) and USB flash drive playback modes; no need for soldering with horn clamps, making wiring convenient; modular design allows for easy replacement. 2. Product Description: Supports MP3 format, automatically plays upon poweron, with a red LED indicator updating during playback. Supports USB flash drive playback (tested with 32G) and TF card playback (tested with 16G). Default mode is TF card; if no TF card is detected, it automatically switches to USB flash drive. If both devices are connected, the playback mode can be manually set. Refer to the most important operating instructions for details. 3. sound quality, featuring a builtin 2W mono amplifier (3W with 5V power supply) for direct speaker connection (recommended with a 4ohm 3W speaker). Equipped with a goldplated 3.5mm headphone jack for connecting headphones or external audio devices. 4. Includes a USB power interface, allowing power supply via a power bank or USB charger using a phone data cable. Also compatible with a 3.7V lithium battery and USB 5V power supply.