They"ll hear you at the far ends of the field when you use this megaphone. Easy to hold, easy to carry, you"ll be heard up to one mile! 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 - just plug in a USB stick with your favorite digital music. Amplify your voice cord-free and with clarity with this lightweight device. Unit includes adjustable volume control and a built-in siren. Requires 8 x C batteries or a 9V DC power supply (both not included). Please Note that the below instructions are to be followed for better use of this item. 1. Make sure the batteries are inserted correctly, observing correct polarity. 2. Remove the batteries when the megaphone is not in use for a long period of time. 3. Drained batteries do not give suffiecient sound volume. Replace the batteries at regular intervals.