 You mean 50% of the volume in your attic needs to be taken in with fresh air? Not necessarily, but you need to have that proper ratio for incoming air versus exiting air. I see what you're saying. Okay. You need to have, there's two types of vents. So there's intake and exhaust. Exactly. So the intakes are low, right? Sure. And that's going to be like the soffit, what goes right along the bottom of the roof line. And then the exhaust is going to be on the top. So that could be something like a ridge vent. Or just placed.