The Wireless Handheld Half-Mile Hailer lets you roam up to 300 feet and blows away conventional megaphones with 50 watts of power. Reach crowds up to 3,000 people. Powerful PA reverberant horn delivers 108dB sound pressure level over the 450Hz - 4kHz audio range. Covers the length of a football field! Lets you see and be seen. Great for athletic events, band practice, field days, public safety, law enforcement, outdoor marketing events crowd control, auctioneers, political campaigns, missionaries - any outdoor event. Includes powerful 50 watt multimedia stereo amplifier with push button siren, built-in UHF 16 Channel receiver, handheld mic with built-in transmitter; shoulder strap. Power with 10 D-cell alkaline batteries (not included) for up to 200 hours; S1460 International AC Adapter/recharger; or S1465 Rechargeable Nicad Battery Pack (requires S1460).