Nope. These are an infrastructure thing, and they do very well and very simply a job you might not have even known to wonder about. Still haven't guessed?
Taking a cue from awesome colleague Melissa C. Lott, I'm jumping on the Photo Friday bandwagon. Here's a thing I ran across in my infrastructure travels recently and thought I'd share. Know what it is?
Just look a second and see if you can identify. I'll post the answer later today.