Answer: Foot Size

Many a child has wiled away a boring trip to the shoe store playing with one of the medieval-looking devices found tucked under the fitting chairs. Hefty in weight, covered in tiny measuring marks, and fitted with heavy sliding caliper-like surfaces, the device has caught the eye of curious children since the 1920s.

It was then that Charles F. Brannock created the first of the hundreds of thousands of devices that would bear his name: the Brannock Device. Brannock was discouraged with the foot measuring standard of the day, a device called the RITZ stick that amounted to a small ruler with a sliding stop attached to it. It required the user to measure the dimensions of the foot individually after reseating the foot for each measurement. The Brannock Device, on the other hand, allowed the fitter to measure every aspect of the foot at once without repositioning the device: length, width, arch, and all.

The device’s sturdy, simple, and effective design led to its eventual adoption as the international standard for footwear measurement and early examples of the Brannock Device are on permanent display at the Smithsonian.