The salesman was demonstrating unbreakable combs in the department store. He was impressing the people who stopped by to look by putting the comb through all sorts of torture and stress.
Finally to impress even the skeptics in the crowd, he bent the comb completely in half, and it snapped with a loud crack. Without missing a beat, he bravely held up both halves of the 'unbreakable' comb for everyone to see and said,
"And this, ladies and gentlemen, is what an unbreakable comb looks like on the inside..."