The mousetrap of aviation. I still have a couple. When all the blinky bits don't blink, the E6B still works. Frequently faster than the blinky ones even when they do. Not bad for general slide ruley stuff as well. No batteries, fast answers with one hand.
In the future, airplanes will come with a dog.
Why?
To bite the pilot if he tries to touch the autopilot.
Otto Pilot. Had one job in the movie. Got it done.