Plastic and boar bristle mix
Boar is really good at smoothing out your hair and is supposed to distribute oil evenly, but doesn't really massage the scalp (or at least, not the way I am used to). The plastic bristles are very flexible, hope they don't break easily.
I love how this brush incorporates both (mostly why I can justify the $38 price tax)
I purchased mine at Beauty.com when they had a sale, link here
I thought this brush was all looks, but surprisingly the plastic is very solid, sturdy and high quality. I'm impressed!
If you're in the market for a pretty hairbrush to put on your vanity, this is probably one of the prettiest hairbrushes I've seen that works well.
I will say that the cushion isn't as soft and flexible as some of the Conair ones I've owned, but it doesn't really affect the performance of the brush.
As a lazy person who almost never brushes my hair, this kind of gives me incentive to. ;)