6-35V power supply Can be connected to active speakers Drive 20W speakers USB replacement audio files,Onboard 64Mbit (8M bytes) storage Serial UART control playback,Relay output (alarms linkage) Power input:6-35VDC Power output:5V Digital input and output:BUSY, UART_TX, UART_RX high level:2.7-3.3 low level:0-0.3 Use a USB-Type C data cable to connect the module to the computer, identify it as a USB flash drive, and copy the audio files directly into Just go Note: The audio file name format is 5 digits, for example: 00001.mp3; 65535.mp3 (The product printed words depending on the batch, but this does not affect use) Color: As Shown Material: PCB Package Contents: 1 x MP3 Voice Module kits Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.