From the manufacturer:
A mechanical pencil-style liner. In formula, soft and creamy, with an intense, rich, colour deposit. Blends on application: dries quickly to a long-wear, non-smudge finish. Versatile. An easy way to line the top and lower lash line of the eye. When applied at a 90 degree angle, provides a thin precision line. For thicker application, apply at a flat angle.