Also known as Klick-Klacks, Whackers, Ker-Knockers, Whack'os, Bangers, Poppers, Knockers, and various other names you wouldn’t want to put into an Internet search engine.
Klik-Klaks consisted of a pair of hard plastic balls tied to a ring by two pieces of string.
The ‘aim’ of the game was to swing them together and make a hugely annoying racket. Kids loved them, but doctors and teachers weren’t so impressed after a frightening succession of serious Klacker accidents.
After a nation outbreak of badly bruised arms and bloodshot eyes they were pretty much withdrawn from sale.