I’m working on a little amplifier from the late ’60s, maybe very very early ’70s, which uses RCA jacks for the speaker output connections. It was most commonly found on very economical and low-powered systems. (The one in question is 10 W per channel, definitely low power.)
Fortunately, a quick dig into the parts drawer turned up some RCA plug shells and a few minutes later, ready to connect.
Easy enough! I won’t be using this one very often, but it joins my collection of speaker cables for whenever I do need it.