The Alto Pro Transport 12 is a 12 inch PA speaker powered by a battery. Thanks to the battery you use the speaker wherever you want. This makes the speaker suitable for presentations, parties and events on location. You play mp3 and wav files from a usb stick or sd card. Thanks to the RCA input it is also possible to connect an external music source. With the included wireless microphone you can call everyone together or give a sparkling presentation. Do you prefer to use a dynamic microphone that you connect to the loudspeaker via a cable? Then connect it to the combined XLR / jack connection.