I had a set of these when I was a kid. I don’t know if my mom bought them for me or they were a gift from someone else. I know it was PRE 1974 because that was the year my father retired from the Federal Aviation Administration. This significance of this will be obvious in a bit.
These are very hard acrylic balls about 2 inches in diameter on a string. The idea was you get them “clacking” together at a fast enough pace and you can “flick” your wrist and they will collide at the bottom with that energy propelling them up so they collide at the top. Making a “clacking” sound.
See the video below. No need to watch three minutes of clackers. But you will get the idea.
They were banned at some point because they were incredibly dangerous. Again, watch the video and you will see why.
When they were banned, my father took mine away from me. And brought them to work.
He was the Operations Manager at the Miami Flight Service Station at Tamiami Airport in South Florida. His Secretary/Statistician was a woman by the name of Betty Healy. I barely remember Betty but I do remember my dad speaking fondly of her and about her being as much of a smart ass as he was (yes, I inherited it).
Apparently, my dad was in his office playing with the clackers when someone from Washington called to talk to him. I have heard this story from more than one person so I have to assume it is true.
Betty told the person that they could not speak to Mr. White at this time because he was in his office playing with his balls.