LIBERTY WITH MP3 PLAYER AND 1 WIRELESS RECEIVER INSTALLED. Perfect for outdoor and indoor events. Covers 2,000 people. AC powered. One wireless receiver built in and built in MP3 player. 10? neodymium driver provides increased dynamic range and it?s lightweight. USB charging port for iPod® or other music playing devices. Great for assemblies, graduations, presentations and any other activity indoor or out.