The Flat Definer is a mini shader, smudger, and precision flat pencil brush. It's flat and thin but has enough density to remain stable and achieve a neat and even application. It's firm with sufficient flexibility and softness at the tip to not pull or skip on the skin. Its main purpose is to provide definitions along the bottom and upper lashline, but it also works nicely as a precision shader for the inner mobile lid, the outer v, to place a sparkly accent or act as a little smudger brush.