This mascara truly has a skinny brush, which makes it great for tightlining the upper lashes, and especially for the bottom lashes. Since it's a waterproof formula it doesn't smudge or flake off during the day. It's my new favourite mascara for the lower lashes for sure! The only thing keeping it from getting 5 stars is that because the brush is so skinny, and the formula isn't very watery, the mascara dries very fast. That makes it hard to apply if you're not fast at applying mascara. For that reason it also isn't the greatest mascara for your upper lashes, but it's still good for getting mascara into the roots, the "tightline" as it's called sometimes. I'll repurchase this when mine runs out, but I'll probably only use it on my lower lashes.