Refill cartridge for the ultimate brow tool. Automatic Brow Pencil Duo has twist-up brow color on one side, brush on the other. Refill easily snaps into place. Brow Basics: Use the brush end of Automatic Brow Pencil Duo first, brushing hairs down to find your natural brow shape. Then use the color end to fill in sparse areas, using short, feathery strokes to shape and even out brow contours. All Estée Lauder brow formulas are fragrance-free and ophthalmologist tested.