I got this product as a gift with the Mary Kay Ultimate Mascara. It is supposed to make your lashes more voluminous after you apply your mascara. I didn't really care for it. I found that it made my mascara clump. I don't use primer, so I don't have anything to compare it with. I don't think that it's worth 21.00$,that's for sure. I do use it to shape my eyebrows though;)