A lash fan is one of the best kept secrets of make up tools. It does exactly what the names says. A lot of mascaras promise to volumize the lash and separate lashes during application. There is a special brush designed to be even more exact than any mascara brush.
A lash fan does not clump mascara onto your lashes. It delicately distributes the mascara in a much more deliberate fashion. You can really get those hard to reach corners and apply to the top of your lashes. You can even highlight your bottom lashes with this little treasure.
I got mine from Sephora for under $20.