1. Download the file to adjust the volume; higher values produce louder sound 2. Micro-USB interface; when connected to a lithium battery, it can charge the battery directly 3. Greeting card module with 8M memory capacity; keypad and light-sensitive models available 4. Ultra-low power consumption module; standby power consumption is 0 5. Freely set the playback mode Brief description of functions: 1. The module comes with built-in memory, 8M optional, and its own USB interface. When plugged into a computer, it appears as a U disk, allowing you to freely delete or replace MP3 audio files. 2. Supports external key control for playback; playback mode can be freely set, including loop or non-loop options. 3. Can be connected to a photoresistor to enable playback when light is detected and stop when no light is present; cycle settings can be customized. 4. Power supply voltage: DC 3.4-5V; compatible with lithium batteries or dry batteries. 5. Ultra-low power consumption design; standby power consumption is "0". Interface Description: 1. USB: Connect to a computer via Micro-USB cable to download MP3 audio files. When connected to a lithium battery, it can charge the battery directly. 2. Charging indicator: Light remains on during charging and turns off when fully charged. 3. Playing indicator: Light stays on during audio playback. 4. Supports downloading multiple voice files; each trigger plays a voice file. Color: As shown Material: PC + Metal Package Contents: 1 x Music Recordable Recorder Board Module Only the above package content is included; other items are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error is +/- 1-3 cm.