AmpliVox Half-Mile Hailer Wireless Loudspeaker: * Reaches audiences up to 3,000" * Weatherproof, reverberate horn speaker * Delivers 108 dB sound pressure level over the 450Hz to 4KHz audio range * 50W wireless multimedia stereo amplifier with built-in receiver * 3 microphone inputs * Shoulder strap * Power with AC adapter or power up to 200 hours with 10 x D alkaline batteries * Optional rechargeable battery pack * Includes lapel and headset microphone with transmitter