Bulletin 855H General Purpose Electronic Horns produce a sound output of 108 dB (A) maximum, which is suitable for most mid-range industrial and institutional, single-status signaling applications. The enhanced version produces sound output of 113 dB (A) max. Our horns have multi-tone and volume control capabilities. You can retrofit the horns directly into most machine panel cutouts or mount them into traditional 4-inch electrical backboxes.