The Champion Sports Megaphones have a built-in siren when you need to get anyone's attention. The adjustable volume control allows you to adapt to different crowds and distances, while the convenient wrist strap makes it easy to hold and transport this megaphone. Adjustable 4 to 8 Watts. Audio Range: 400 yds; Length: 7"; Power: 4 W to 8 W; Power Source(s): 6 AA Batteries (Sold Separately).