Not to be dark, but I keep seeing needless, stupid deaths by carbon monoxide poisoning. It’s so avoidable. It has been on my mind to get these for months, and then recently I saw a 14 year old boy die on vacation bc of CO poisoning. So I bought a 3 pack of these. They plug in and work right away and you can travel with them! Best $72 I’ve ever spent if this prevents such a avoidable death of a family member of mine Travel tip Home electronic Home Safety LTKTravel LTKHome