If you have a vacation cabin that sits idle a lot, eventually you'll have stagnation odor, which smells the same as chronic odor. What's the difference? If you have chronic odor, this will fix it for about a week or so, then it will come back. If you have stagnation odor, this will fix it until you leave the water heater idle for a month or more. So if you can't afford a powered anode for chronic odor, this is a cheaper alternative. And if you have a vacation cabin, it may be the only thing that will solve the problem. If you want to buy this, go here.