Yellow button with red text.
Ah, vintage sexism! Balls Candy used the slogan "You Need Balls To Conquer The World" and other variations to say, "These days, women have finally come into their own – with pants and permanents, muscles and makeup. But there still are a couple of things we can’t lay claim to right?" Balls Candy was trademarked in 1977 and they were sour candy balls, that said women should "suck on some" for some encouragement. They ran this campaign through 1985.
Source: Anorak. (2014, February 5). Vintage Sexism: BALLS – ‘Candy To Give You Courage’. Retrieved June 15, 2016.