This is the Anastasia brow brush. It says "15" on it but I don't see any other brow brush they make. It is described as "cut, angled" brush.
The hairs are short, firm, and dense. It has a short, thin handle which makes application an absolute breeze.
I find this brush to be just perfect. I use just the tip flat for the outer part of my brows, which are basically nonexistent. I use it flat vertically for the parts near the bridge of my nose where I need just a little fill. I never get any powder fall out and the lines look natural.
Before this I was using MAC and Nars brow brushes, and I liked them but sometimes I felt like the brush wasn't depositing enough product, or the lines ended up too thick or uneven, and I had to use much shorter strokes as well. With the Anastasia one it's a lot less effort to get an even better result, so I am very happy with it.