Key benefits Enables offline music playback from SD cards or USB drives, without relying on network access. Flexible power option using your own TR18650 battery, allowing portable use. Simple, clear speaker wiring with colorcoded terminals (red positive, black negative) for quick setup. How to use Install the TR18650 battery first, paying attention to polarity (positive and negative). Battery is purchased by yourself. Insert an SD card containing song files into the SD card slot, or insert a USB flash drive containing song files into the USB interface. Connect the speakers using two wires: red is positive, black is negative. Specifications and compatibility Media input: SD card slot or USB interface for music files. Battery requirement: TR18650 (battery purchased separately). Speaker connection: twowire link with red = positive, black = negative. Use scenarios Home listening: Use SD card or USB drive to play a local music library, powered by your own TR18650 battery for cordless operation. Outdoor activity: Portable background music during camping, picnics, or outdoor projects where wall power is unavailable. Small gatherings or classrooms: Local playback from stored music files for events, presentations, or instructional use without external power dependence.