(FORTUNE Small Business) – The most interesting products, by and large, aren't the ones that draw attention to themselves. After all, anyone can invent something with lots of bells and whistles. No, the most interesting products are the ones designed with such understated elegance, such a sublime marriage of form and function, that they hide in plain sight, entering the fabric of our lives without our even noticing. And nothing fits this description better than the classically inconspicuous Brannock Device.

Never heard of the Brannock Device? Don't worry--neither has anyone else. But that just underscores my point, because while you may not know the Brannock Device by name, you most assuredly know what it is--it's that gizmo they use to measure your shoe size. It might not seem like a cultural icon at first, but look around the office, airplane, or wherever you're reading this copy of FSB, and consider: Every single person you see--and probably everyone you can think of--has at some point placed his or her foot in a Brannock Device. It's truly a universal touchstone. Not bad for a gadget that nobody can even name, right?

The Brannock Device was invented by one Charles F. Brannock, a man who deserves a loftier place in history than the forgotten corner to which he has heretofore been consigned. Born in 1903, Brannock grew up spending time in his family's Syracuse, N.Y., shoe store, where he became interested in inventing a better foot-measuring device than the crude, ruler-like implement that was then in vogue. He spent his college days obsessively tinkering with prototypes and updating schematic drawings (often at all hours of the night, as his sleep-deprived dormitory roommate later recalled), and by 1927 had perfected and patented the Brannock Device. It was a marked improvement over previous tools, because it measured not just foot length but also foot width and arch length. Originally used only in his family's store, it soon caught on throughout the industry and is now used around the world. Although Brannock died in 1992, the Brannock Device Co. still produces his gadget--over a million of them have been sold.

Seventy-four years after its invention, the Brannock Device is essentially unchanged. With its black-and-chrome surface and sleek curves, its happy jumble of graduated calibration markings, its two sliding attachments, and its oddly balanced asymmetry, it remains an immensely pleasing object. And, like most superior examples of industrial design, it feels utterly modern, as if it had been created yesterday. Best of all is its spectacular functional specificity--simply put, it's a perfect execution of what it was meant to be.

Charles Brannock, as it turns out, was pretty functionally specific himself. In fact, he appears to have been as singularly directed as his invention. He was born in Syracuse, grew up in Syracuse, attended college in Syracuse, worked in Syracuse, and eventually died in Syracuse. He named his device after himself, then named his company after the device. A lifelong bachelor, he was married only to his invention. And he never invented anything else.

Brannock's life might seem somewhat unexamined, but I prefer to view him as a visionary--the rare man who was content with what he'd accomplished. You see, unlike another great American creator, Orson Welles, who spent a lifetime fruitlessly attempting to recapture the glory of Citizen Kane, Brannock understood that perfection doesn't require an encore.