DC 9-24V wide voltage power supply 9-Channel one-on-one trigger interface, triggering up to 9 music Low level trigger version and directly using GND as a trigger signal Supports MP3 and WAV decoding formats, and audio file sampling rates up to 48KHz Supports TF card (up to 32G) storage and must be in FAT32 format(not NTFS) Micro-USB Socket: Connect to PC and download music files. Equipped with a 30W Class D power amplifier, it can directly drive 4-8ohm, 10-30W speakers External warning lights can be connected and voltage is same to input voltage DIP switch is set with 8 trigger working modes Potentiometer and volume button adjusts volume Module Size:76X58mm 3Bit Red Toggle Switch:Set 8 different triggering modes, which must be powered on again after changing the mode. Light/Alarm Output: Output voltage is the same to input work voltage. It can connect alarm/warning lights. Two Indicator: Green after power ON and red when playing. (For Power supply and Playback) Colour:Black Material:abs type: A:low level trigger-bare board L30T Package Contents: 4 x Player power amplifier 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.