Benefit Cosmetics' Twice As Precise - Precisely, My Brow Pencil Duo is a set of two full-sized ultra-fine brow defining pencils. The pencils come in a 12-hour waterproof formula with a thin crayon that creates natural-looking brow hairs.Fill the brow in small, hair-like strokes of color, then soften and blend the color out with the built-in spoolie brush.