Attention, fellow commuters shuffling eastward from Union Station toward Daley Plaza. Please note the shiny, metal rock-climbing clip (or “carabiner,” to fellow-alpinists) dangling from my Swiss Army book bag. It is both a flag flown to identify me to other kindred survivalists and wilderness enthusiasts, as well as a visual reassurance to others that I have extensive experience in the extreme outdoors, and can be trusted in a survival situation.

True, on a day-to-day basis I’m more likely to call upon my carabiner to secure my Eddie Bauer travel mug or Camelback water bottle to my backpack. And yes, it’s also true that my red carabiner is technically a keychain, the aluminum clearly stamped with the words, NOT FOR CLIMBING. But still, it should instantly identify me as the type of person who is likely to also carry a small Leatherman multi-tool (you might call it a “pocket knife”) on his or her person. Which I do. Can I claim to be “ready for anything”? No. But I am ready for several things. Dozens even.

The point is, if a survival situation were to arise during our walk across town, you can (and should) count on me. If a section of the 300 block of Adams were to suddenly collapse, requiring us to rappel to safety, I will jump into action. If there is any ice climbing to be done between the Tazo Tea on Madison and the CVS on State Street, you’re going to want me “on belay.” I can calmly walk you all through what I learned at my local climbing gym, during an intensive three-hour group class that I once took there (during which we used actual carabiners, intended for climbing.)

My emergency readiness should be easily apparent, based on the carabiner I’ve displayed on my book bag. If you’re looking for the most experienced and enthusiastic outdoorsman on this sidewalk, I think we can all identify who he is. (It’s me.)

Also, this backpack isn’t just some Jansport book bag. This is Swiss Army. This backpack was specifically designed to meet the rigorous demands of Swiss military units traversing the Alps under cover of darkness. That’s why it’s black. And so, while some might call the nylon webbing daisy chains sewn to the outer pocket “useless” or “mainly decorative,” it is here, clipped to the third loop down, where my shiny, red carabiner feels most at home.

In between wilderness adventures, I have a day job much like you. I can’t utilize my Ex Officio convertible hiking pant on a typical Monday through Friday. And, on average, I can only display three or four of my many, many pieces of North Face apparel during my commute (with the obvious and exciting exceptions being a commute during a snowstorm or extreme cold.) You may have noticed my Merrell trail runners, which I wear to cushion my assertive and vigorous walking pace, to and from the train. But otherwise, my identity as a survival expert is kept mostly hidden. Your only clue will be my carabiner keychain, that mark of a true outdoorsman. And although it was an impulse buy in the checkout line at REI while my wife and I were purchasing our almost-matching pairs of Chaco sandals, this carabiner was earned, not given.

So please, do take note of my carabiner as we exit the train together. And if you also proudly wear this “Mark of the Mountains” on your own book bag, I will give you the silent, knowing nod of a fellow explorer.