MUA Eyebrow Pencil Mid Brown MUA Makeup Academy Micro Brow Pencil. This ultra-precise, sharp eyebrow pencil creates fine, hair-like lines that help to fill out and define your brows. The dual-ended brow definer has a retractable pencil on one end and a spoolie on the other to help brush through your brows and distribute product. The long-lasting, intense-pigment formula lasts all day long without smudging or fading.