It's the "extra noir" (extra black) khol pencil by Agnès.b.
I got it about 9 months ago, I use it everyday and it's still really big. At the beginning it was longer, like 1/4 more. I love it, it lasts, it an intense black and looks beautiful when you put it on. I also like the design, the little artwork on the right (at the bottom).
It costs 9,90€ and is available in 7 other shades.
Agnès.b is a French brand, so if you don't live in France, I guess you can order their products. I hope so, because they're cool. :)