These products are generally put in in properties and other structures to alert occupants to the presence of a hearth also to aid evacuation. Dr Zzeus Q&A: If fire alarm indicator products don't satisfy the expected standards, is the program compliant? They are usually tricky-wired to some conventional hearth alarm https://www.firesense.co.uk/type/conventional-fire-system/conventional-sounders-vids-vads/