So this entire spiral region is known as the cochlea. And as the pressure wave moves into the cochlea, it bounces off and moves back, eventually hitting the round window. The round window is a second membrane inside our cochlea that basically helps the propagation and the creation of that mechanical wave. So recall that one main difference between air and liquid is that liquid is not easily compressed. So inside this cochlear region, if we didn't have these membranes, the pressure wave would not be able to travel because we would not be able to compress that liquid. But because of the vibrating round window, and because of the vibrating oval window, we basically have this propagated mechanical wave inside the cockpit.