 You've heard me talk about R-values, the resistive value of insulation. And insulation plus a sub-sheathing or plus a foam sheathing or, you know, everything has an R-value or resistance. Even a piece of paper does. If you take a hairdryer and you hold up a piece of paper and you heat up the hairdryer against the paper, on the other side, it stays cool, right? Because that paper has resistance to it.