So, earlier I said that the flat of the curve is the greater the ability of that buffer system to actually prevent a drastic change in PH from actually taking place. So based on the curve, where exactly is our flattest slope? So actually I've marked down the flattest slope. 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.