It's a chain guard and apparently they cannot be purchased from a bike shop unless you find one that has been salvaged. I'm kind of bummed about that. I mailed mine to Honest Paul at the Honest Bike Shop in Rochester, MN; he checked to see if he had a match and he doesn't. Now we're communicating with voice messages and he says he doesn't know why I'd want this back... I do because it's mine and I still hope to find a replacement! He did offer some suggestions, there's a bike shop in Grand Forks? and there's a company in Wisconsin that owns the Schwinn Company? He's very helpful, Paul is, but bottom line is that I don't have a chain guard and I liked having it.
It's winter anyway.