The Butterfly Eyebrow Pencil is a popular brow product known for its fine, precise tip that allows for hair-like strokes to create natural-looking eyebrows. It often has a long-wearing, smudge-proof formula and may include a built-in spoolie brush for blending. The pencil is typically dual-ended, with one side for filling in brows and the other for grooming. It’s great for defining, shaping, and adding volume to eyebrows with ease. Some versions are waterproof and come in multiple shades to match different hair colors.