Sigma explain the product to be "a buffer brush that can be used to blend powder or liquid products" and i really agree. Initially i wasn't sure about using it for my liquid foundation, but after using it a few times, i found a way that worked and now i often pick it up before looking for my 187 brush. It blends various products so well and takes little effort. I find myself using it for not only my foundation, but powder and blush too.
I think the reason this brush is so successful is due to the density of the bristles. They're packed in so tightly yet there is still movement, so it goes where you want it to giving you that flawless feel, and because the bristles are tightly packed, your make-up doesn't get wasted. So its more on your face, and less down the drain when you wash it.
The Sigma F80 retails for $16, which works out to be around £9.50!
Do any of you already have this brush? What are your thoughts on it?