 Well, the one thing, Chuck, the one thing that really is a killer on the one going through the roof, especially during the wintertime, that pipe that goes vertically is carrying a real moist, hot air. Hot, humid air. And that pipe, if it's not insulated as it goes up through the roof, will cool, and then that lint or whatever is getting by the trap in the dryer is collecting to the pipe on the outside, and that's going to cause it to clog. The other part of that is if it goes up through the...