Microbeads are tiny plastic beads barely visible to the eye. Short for microscopic beads, they’re usually about the size of the tip of a pencil. They’re so small you may have used microbeads without knowing. “They are used in consumer products — a wide range of consumer products including sunscreens, face creams and even toothpaste,” said Jake Vander Zanden, a professor of limnology at UW-Madison.