Mega Phone PA Speaker makes megaphones ideal for transportable applications like field publicity, controlling pandemonium, etc. Additionally, it directs the sound waves in the direction of the horn's direction of travel. Weather-resistant paint is used to finish the rugged unit. This speaker is great for both mobile and static uses. The sound volume of a MegaPhone PA Speaker is increased by increasing the acoustic impedance, matching the vocal cords' impedance to the air, so that more sound power is radiated.