Real Techniques Expert Face Brush
As others have mentioned, it is quite dense but downy and solid (if that makes sense) enough to "buff" the base onto skin.
This brush came packaged.
I find that it functions best when I then make use of the brush to distribute and mix it and apply base in dots. It only take up manner too much and then does not mix correctly, although I attempted to dip the brush in the merchandise first. I favor it for heavier/thicker bases like Clinique Stay Matte or MAC Studio Fix, I do not believe it'd operate with bases that are light well, it'd only drink the merchandise up!
No side effect has been experienced by me at all, happily. In addition, I LOVE the fact the brush has an end that is flat so that it stands up on it is own.