They sold them in most car shops. My Dad had one on his Astra and on his Cavalier. It had a wire in the middle and was to ground out the car so you wouldn't get electrostatic shocks when you touched the car as you got out.When I was a kid the grown ups were very scared about something they called "Earth Radiation" and the cure for that was wearing copper bracelets. You can still buy those, and they are miraculously solving almost any problem you can think of:
View attachment 174698
The grown ups had also invented a special rubber strip that, when mounted on your car, removed motion sickness:
View attachment 174700
Those grown ups back then were so much more clever than grown ups today.
Edit: Radiation can be harmful, like in the case of the OMG particle, a cosmic radiation particle containing energy equivalent to a baseball traveling at 60 mph. You might even feel being hit by one of those, even though they are extremely rare.
Wear a pair of Sketchers and some man made socks and that is definitely still has a purpose; They don't sell that device anymore but memory foam footwear and nylon will zap you big time!