The Liner brush: A small angled natural or synthetic brush. Why you need it: It's multi-purpose as it can be used on your lash line for eyeliner and your brow to fill it in. Plus it is the most user-friendly of the eyeliner brushes due to its easy-to-maneuver slanted angle. How to use it: To apply liner, place the brush on the inner corner of the eye and pressing into the lash line,"walking" the brush across to create a perfect line and to create "a winged edge," by simply pulling "out slightly past the edge of the eye." For the eyebrows, use it to "fill in sparse brows with powder," by using short strokes over your natural brow shape.