The PMP53IN 50W Professional Piezo Dynamic Megaphone from Pyle Pro is a power horn speaker/megaphone capable of projecting your voice in utmost clarity up to a mile. It is well suited to be used both indoors and outdoors when your voice needs to reach a large crowd. The variable volume control adjusts your speech volume to the optimum level. The built-in siren is used to catch the attention of your audience. An external audio device such as an iPod or iPhone can be easily plugged in using the 3.5mm double-sided male audio cable. The tough housing braves harsh weather conditions and is used by the U.S. Army, schools, sports coaches, and more. The unit runs on 8 C batteries.