Megaphones and Sirens

Megaphone is a device that amplifies the human voice and projects it in a directional cone-shaped beam, allowing to communicate with large crowds or over long distances. They are typically handheld and portable, and may be powered by batteries or a built-in microphone. Siren is a device that produces a loud, distinctive sound, often used to signal an emergency or to alert people to danger. Sirens may be mechanical or electronic, and can produce a wide range of sounds. They are used by emergency vehicles such as ambulances, fire trucks, and police cars, as well as by ships and boats to signal their approach or to warn other vessels of their presence.