Converts all AmpliVoxÂ® sound systems to wireless, providing an instant boost to any presenter's stage presence. Switch selectable radio channels give users two operating frequency options, making interference easy to avoid. Clip-on condenser lavaliere microphone features a low profile design and a sensitive uni-directional pickup pattern that's perfect for professional public speaking engagements. Dependable transmitter ensures a consistent signal up to 300 ft. away. For added flexibility, the receiver may be powered by either a 9V battery or the included AC adapter.