Pyle PMP58U

They'll hear you at the far ends of the field when you use this Pyle Pro Professional Piezo Dynamic 50-Watt Megaphone with USB. Easy to hold and easy to carry, it lets you be heard up to one mile away. The microphone is built into the rear end of the unit and is activated by a trigger on an ergonomic pistol grip. Use this super-powerful, 50 watt megaphone indoors or outdoors. Plus, it's got USB playback so you can plug in a USB stick with your favorite digital music.