It's right at this point. This is the point where we have the flattest slope. And so what that means is this is the point where we have the greatest ability of that buffer system to actually resist and prevent that change in PH from taking place. Because the flat of the slope is the smaller the change in the y value is and the smaller our PH change is. Now, if we look at this corresponding value along our y axis, we see that it's somewhere here. And so this is equal to a PH of about 4.75.