 either the window, which is fine, or down the stairs, and you want to protect the hallway and the stairs because that's where you exit. So if you're in an old house, the number one detector that's the most important is the one in the bedroom hallway, and if you have a stairwell, that one's important. Also, exiting, it's a big deal. So that's kind of the story. One way to tell older detectors, and I kind of chuckle about this because I still see this,