. . . . . . . . . . . "Acoustic hailing device"@en . . . . . . . . "An acoustic hailing device (AHD) is a specialized loudspeaker that produces sound at high power for communicating at a distance. AHDs vary in design, output, and usability."@en . . . "24288049"^^ . "6270"^^ . . . "An acoustic hailing device (AHD) is a specialized loudspeaker that produces sound at high power for communicating at a distance. AHDs vary in design, output, and usability."@en . . . . . . . . . . . . . . . . . . . . . . . . . . . "1106308488"^^ . . . . .