Hi there, my name is Nesim and today I will try to answer your question as brief as possible. Now, Gas Safe - Safety Device is a fire safety device which is one time investment to ensure the safety of your home and family from any fire hazards. And also one of the best Gas Safe - Safety Device is the Generic Gas Safe 100% automatic Gas Safety Device. You should definitely google the one I mentioned and you'll get a much better picture. Hope this answers you question, Best Regards, Nesim