So here's the deal with the Luxe Light Brunette Faux Brow Enhancing Pencil – it's basically your secret weapon for brows that look totally natural and full. People are obsessed with this thing because it seriously makes it look like you've got real hair where maybe you don't, and it bulks up your brows without looking fake or overdone. The coolest part? It's got this double-brush tip situation that makes doing your brows super quick and precise. Like, you can literally double the fullness of your brows in seconds without having to grab a bunch of different products. You get total control when you're using it – it draws on just like actual hair, so you can add depth and really define your brows exactly where they need it. The formula is crazy thin, which means it goes on smooth and stays put literally all day long. It's got this really fine tip that makes it perfect for everyday – you can outline your brows and fill them in with crazy good accuracy. Here's how you use it: give the pen a good shake first to get everything mixed up and working right. Then just lightly draw from the inside part of your brow heading toward the arch, using little upward strokes. When you get to the tail part, change up the angle a bit to define it, and boom – you've got perfectly shaped brows that totally frame your face.As for what's in it, it's got a water-based formula with stuff like propylene glycol and butylene glycol that keeps everything smooth and actually takes care of your skin at the same time.