In the year 1927 the Plus Four Wristlet Route Indicator was invented. This new fangled device showed the wearer a map of their location and by merely twisting either the upper or lower nobs the map unwound with a viewfinder showing a section of the road that they were on. With 20 interchangeable maps this device would have been highly useful to those who traveled often and it is a bit of a surprise that these did not even make it to mass production phases.
Beyond the mapping feature it also included a way to keep score in Golf, perhaps this would have been more suited to come with maps for a golf course rather than cross country? MailOnline