Here we have another duo-fiber brush. As I've said in my post on MAC's 130 brush, I've never been a big fan of these types of brushes. But I want to find one that changes my mind about all the rest.
The 131 brush has a combination of natural and synthetic brush hairs. The brush is not dense at all - which is, again, one of my problems with duo fiber brushes. The hairs are very VERY soft though, you won't have to worry about scratchy application of whatever product you use it for.
I originally bought this simply because it looked cool, and I was trying to get in on the duo fiber bandwagon. I tried it initially with liquid foundation, and didn't like it for that. The lack of density makes blending liquids out next to impossible for me.
However, my beloved MAC 109 brush (featured in my Top 5 Brushes post here) unfortunately met its demise recently (the brushes detached from the ferrule, womp womp). So I needed another tool to apply my face highlight with. I broke out the 131 and like it. It's very hard to apply too much product with this brush, so I don't really have to worry about over doing it with my highlight. But with that said, it's also hard to blend out product if you do apply too much (goes back to my problem using it for liquid products).
The 131 isn't my holy grail brush, and it hasn't lived up my love that I have for the 109. But it does the job I want it to do, and down the road I might find more ways to use it in my makeup routine.