The onboard SPI Flash can realize related functions, which is more cost-effective. It can be connected to a computer via the MINI-USB port and used as a USB flash drive to download MP3 songs directly from the computer. 15 buttons to control music play/pause, previous/next song switching, and volume adjustment. With 3W external amplifier. SPI Flash and TF are used to store MP3 songs. You can choose one from the two. If both exist, the TF card be played first.(Does not include TF card), Weight: 0.2094391489 pounds, Manufacturer: Jaywool