Lash Exact is advertised as "no clumps on the brush or on your lashes". Maybe it's just me, but I think they need a new slogan! You can't predict if you are going to get a useable product when you buy a tube of this mascara. Half the time is a clumpy, gloppy, thick goo that is almost impossible to apply - and the other half of the time? It's one of the best mascaras I've ever used. The product coats every lash, and does not clump at all, no matter how much you apply. It does not build very much thickness or length, but instead defines the lashes you have for a natural look. One application lasts all day with very little flaking off, and it's easy to remove the product at night.
The brush is very odd - it isn't bristley like most mascara brushes. Instead, it's made of rubber and has little semi-flexible nubs, almost like a miniature comb. All in all, the applicator brush is a bit stiff, so you have to be careful not to stick it in your eye. It's painful enough to do this with a regular mascara brush, so I imagine you could seriously damage your eye with this one.
Save your receipt when you buy Lash Exact, just in case you get hold of one of the clumpy, gloppy tubes and have to return it!