So it utilizes the countercurrent multiplier system to create a concentration gradient found inside the interstituum. And what that ultimately does is it basically allows our Loop of Henley to absorb more water, and allows the nephron overall to absorb more water. And this concentrates our urine that is produced by the nephron. And at the same time, it utilizes as little energy as possible. So the only time we actually use any energy within our Loop of Henley is within the thick ascending loop of Henley. And we'll see why energy is used in this segment in just a moment.