Wrist-top Navigation Device from 1920

"Old watch-like navigation gadget from 1920"
CrunchGear (August 18th, 2008)

"Way, way, way, way, way before the days of the Global Positioning System, people had to navigate using devices like the Plus Fours Routefinder, shown above...."

It looks like a Dick Tracy wrist radio, and displays one of a set of small scrolling maps. Smart, efficient, and never really took off. Possibly because there weren't all that many cars in 1920.

There's a good photo of the device.