A standard goal electronic sounder for fireplace, protection and industrial applications; the Sonos Sounder Beacon is Qualified to EN54. Place only, this advice causes it to be crystal clear that where by a visual indicator is employed like a Major alarm, it must be a VAD certified to EN 54-23 https://www.firesense.co.uk/type/conventional-fire-system/conventional-sounders-vids-vads/