It's Maybelline's Define-a-Line Eyeliner and it's my all-time favorite. I've tried quite a few higher-end and more expensive eyeliners in the past few years thanks to Birchbox, as well as several other drugstore brands, but none of them has even come close to taking the place of Define-a-Line in my heart and makeup bag.
Most days I use the Brownish-Black shade, which is a nice dark brown that goes well with my fair coloring and blue eyes. I've also started using the Slate Gray pretty regularly. The Chestnut Brown was a recent purchase for me that I can't wait to try it for a change of pace. To be honest, I seldom use the Ebony Black, only because I feel like black eyeliner tends to look harsh with my coloring, but when I want a more dramatic look, I'm happy to have it on hand.
As I mentioned, one of my favorite things about this eyeliner is that it goes on very smoothly. It doesn't tug or pull at my lid at all. It's an automatic liner, so it doesn't need to be sharpened, which is also nice. I haven't had any problems with unwanted smudging or smearing (although I do purposely smudge my bottom line a bit to soften it). And it removes cleanly with my usual eye makeup remover.
So if you're looking for a fantastic eyeliner that's also easy on the budget, I definitely recommend trying Maybelline's Define-a-Line Eyeliner!
Have you ever tried this eyeliner? What's your all-time favorite brand/shade/type of eyeliner?