This is a new edition of their blush brush. I think it came out sometime in 2012.
I'm not sure what the hair is made of, but it's definitely natural, probably goat.
The brush itself is dense, pliable and very soft to the touch, but not as soft as synthetic brushes.
However, it applies powder products so much better than synthetic brushes. For reference, I used the Ecotools blush brush before, as well as the Everyday Minerals kabuki. Both were nice, but Chanel is excellent.
Not because I'm a snob who only thinks expensive products are better, but because this really blends my blush better, makes my powder less cakey and generally distributes all powder products in a different way.
With synthetic brushes, it was hard to blend blushes, but with this even the most pigmented ones (e.g. Illamasqua) go on like a dream.
My powders used to look a bit heavy on my face, but the Chanel brush helps me use less products which in turn makes powders look more natural and even blurs some of my minor imperfections.
Also the size is excellent for so many things: blush, bronzer, contour, powder.
The only downside is that it sheds. The first week it shed about 10 hairs in total, then it started losing one hair per application and after about 2 -3 weeks it stopped. The loss is not so big that it became less dense, but it's still very annoying, especially because this is not a chep brush by any standards.
I'm not sure I would recommend it. Although it performs wonderfully, I still think there might be some equally good, non-sheding brushes out there.