1. 4 trigger inputs available and triggered by negative pulse/GND (low level signal). 2. Equipped with a high quality audio decoder chip that is able to decode MP3 and WAV audio formats. 3. Built-in a 8MB flash memory by default, which is able to store total of 8 minutes long MP3 files of 128Kbps. 4. Supports max. 32GB micro-SD card. 5. Load audio files to the internal flash memory easily through USB connection to computer.It'll be detected as a USB flash drive on computer. No need any program/software. Supports multiple functions/trigger modes. The function/trigger mode of each input can be set individually through a configuration file. Can be controlled by buttons, switches or relays. Built-in 10Watts class D amplifier for a great sound output. Adjustable sound volume through the small blue potentiometer. Wide power input(9-24V DC) and stable performance. Industrial grade design and strong anti-jamming capability. Working voltage: DC 9V-24V Working current: ≥1000mA Standby current: ≤10mA Power Consumption: ≤10W Flash memory size: 8MB Audio format: MP3/WAV Color: As Shown Material: Plastic+Metal Package Contents: 1 x Triggerable Audio Player