Check the listing for details. MP3 Alarm Speaker/MP3 Player Siren - Positive Trigger Version. Condition: New. Listed at 45.95 USD. Please note that this is the Positive Trigger Version Features: Adopts solid magnet to make sure loud volume and great sound quality. Two versions (negative trigger and positive trigger) Built-in high-quality MP3 player soundboard. The function/trigger mode of each input port can be set individually through a config file. Support 7 main trigger modes and 5 assistant trigger modes. Built-in 4Mbytes flash memory by default and supports max 32GB micro SD card. Able to update audio files by connecting the micro USB port from the internal soundboard to a computer. -It will be detected as a USB flash drive on the computer. -When there is an inserted micro SD card on the board, the computer reads the micro SD card directly. In the same way, the device will directly play the sound from the micro SD card. Built-in mono 15 watts class D amplifier and possible to connect with an audio output jack. Adjustable sound volume through the small blue potentiometer on the internal soundboard, and also possible to connect with external buttons to adjust the volume. Industrial grade design and strong anti-jamming capability. Dimensions: 79 x 76 x 100 mm Size of the internal soundboard: 45 x 45 mm Technical Parameters Working voltage: DC 12V-24V Working current: ≤2000mA Standby current: ≤10mA Power consumption: ≤15W Flash memory size: 4MB Audio format: MP3 format 32Kbps-192Kbps Sound pressure level: ≤110dB Protection class: IP65 PLEASE NOTE: To update the audio files (micro SD card or mini USB port for built-in flash) you will need a screwdriver to take the unit apart as in the picture below. Also orders for a quantity of 100 or more units we can upload your audio files to the flash memory for you. Please contact us for details.