Edwards Signaling 870 AC & 871 DC Series are low-current, high decibel flush mount vibrating horns for heavy-duty use. It has been designed for wall or panel installation and projects less than 1" (25mm) from the mounting surface. Suplied complete with trim plate. Designed for indoor installation. Horn mounts in Catalog No. 870-B back box (ordered separately). Applications include ceiling and wall mounting in corridors and manufacturing sites. Also, ideal for scoreboards. Used wherever a distinctive, urgent signal is required for timing, scheduling, paging, general alarm, and warning.