If you need to be heard in a crowd, this is a great way to do it. Totally portable using 8 x C batteries (not included) for approximately 8-hours of operation. The powerful 25W amplifier and horn speaker will help your message be heard up to 500m away! The microphone can detach from the back of the unit thanks to a curly cable, allowing you to hold the unit above your head (in a crowd), but still speak clearly into the microphone. A built-in siren generator is also included, which is sure to get you attention. The shoulder strap makes it easy to carry and trigger activation provides straight forward operation and power-saving while not in use.