Round brushes may be the most elusive brushes of all time. Yes, we see them a lot and understand that we should probably own one, but there are so many variations that seem to remain mysterious. A quick rundown: Round brushes are perfect for creating that voluminous, classic wavy blowout that we all hope to run into an ex with. However, there are so many different sizes of round brush, with different types of bristles, and those two details will determine exactly what your style looks like.