In 1927, we didn't have global positioning systems or micro LCD displays. But we did have the Plus Four Wristlet Route Indicator. A map that fit on your wrist, a driver could turn the knobs to scroll up their route in a manner far more dignifying than the giant-map-fold-curse-refold maneuver.
While a bit smaller than the average map, when the driver exceeded the map's limitations, they could simply swap it out for another and continue on their journey. Coming with 20 maps, the Wristlet Route Indicator ran £5 in 1927. With inflation, that number is the equivalent to about £50. Compared to the average cost of a GPS receiver today, that price doesn't sound all that bad, especially because the device is about 100 times more charming than the "turn LEFT in FIFTY metres" lady. [DailyMail via GizmoWatch]