 It's a sustained release, the mosquito dunks. They do about 100 square feet of surface water, regardless of depth. And the lifespan on that is about 30 days. And then you just reload with another mosquito dunk. If it's, you know, 25 feet, you can just break a little core of that dunk off or use the mosquito bits. But that's certainly easier than fishing and trawling for mosquito larvae. That's for sure.