1950s car armrests FTW

I desperately need this car armrest seen in the November, 1950 issue of Popular Science. Is the armrest safe? I have absolutely no idea, but it sure does look comfy. I'm curious if there is an arm rest on the other side, too. This gadget makes a long day of driving look much more tolerable.

"Easy-chair comfort for the car driver was provided by an adjustable armrest which hooks over the back of the front seat. The driving aid—a flexible metal bar with a sliding cushion––fitted all cars. A small lever permis the foam-rubber cushion to be adjusted to the most comfortable height, then locked in place. The metal bar is covered with fabric to prevent damage to the car upholstery."

Bring back bench seats!