Called the Plus Fours Routefinder, this little British invention was designed to be worn on your wrist, and the “maps” were printed on little wooden rollers which you would turn manually as you drove along.
The tiny scrolls show the route as you motor along, winding continully to display the bit of the road you are on. There's even a little "Stop" instruction at the end of the route.
OK, it doesn't use satellites so it's really just a Nav, but as it was invented in 1920’s this could well be world’s first personal navigation system.
It was a great idea, but as there were so few cars on the roads in the 1920s, the device never really took off.
Now consigned to the scrap heap of history, the Routefinder is one of many gadgets patented by inventors who were hoping to strike it rich with their bizarre contraptions.
It’s part of a collection of weird and wonderful inventions, all conceived between 1851 and 1951, which have gone on display at the British Library in London.