We use them all the time, but do you actually know how a zipper is made? Or where they come from? They haven't all been outsourced to China. At UCan Zippers, the last zipper factory in L.A. and one of the last in the United States, they'll happily show you around on a Thursday afternoon. Prepare to be amazed, because in this factory of burning bright paints, bobbins, powders, pulls, bottles of chemicals, lightboxes, bizarre thunking machines and strips of toothy material, you'll learn that more goes into a simple slider than you ever imagined. Your guide probably will be one of the Lai brothers, who run the place alongside patriarch Paul; as teenagers, they lived for Velcro and buttons — before accepting the inevitable. Outside, check your fly: If there's a UCan on there, it came from here. —James Bartlett
1930 Long Beach Ave., dwntwn., 90058. (213) 749-2610, www.ucanzippers.com.