That would be “The Plus Four Wristlet Route Indicator” from 1927… Not only it’s the earliest navigation wrist gadget, but it’s also wind-up ! Something your 5-year old would love.
Insert an interchangeable map into this route indicator and never get lost – even if the whole nav-sat system goes down. (More info).
I had one of the orginal PDAs when they came out. But, of course, they didn’t call them PDAs back then….they called them PADs! 😉