 They're basically little cylinders. These are the so-called data loggers. They're about the size and shape of a glasses case. There's one that has a copper cap on top. That's the dissolved oxygen sensor. And then there's another one that's all black, and that is our conductivity and temperature sensor. All Huizenga has to do is connect a cable and download the data. We can hook it up to our computer, and then we can see that data and how it changes throughout the day and over weeks.