A megaphone, speaking-trumpet, bullhorn, blowhorn, or loudhailer is usually a portable or hand-held, cone-shaped acoustic horn used to amplify a person's voice or other sounds and direct it in a given direction. ... It also serves to direct the sound waves in the direction the horn is pointing. Perfect for announcements in colleges , schools, drills , offices , police , including siren noise You can record music, voice and play subsequently it has 240 seconds recording capacity Also, you can playback from bluetooth, USB or memory card recorded voice , speech ,anthems, music and so on USB Chargeable , cable provided.