Casio’s first hit was a finger ring for smoking a cigarette down to the nub.
Toshio Kashio invented it in postwar Tokyo, when cigarettes were scarce, so people could smoke while working with their hands, and his brother Tadao turned it on a lathe. Its profits paid for developing an electric calculator, and in 1957 the four brothers founded Casio Computer to make it.
Casio on Brandseum