Lancome Cils Booster XL Enhancing Lash and Mascara Primer is a conditioning formula for visible performance. Infused with micro-fibers, Vitamin B5 and Vitamin E. This revitalizing lash primer will improve lash results, thickness and curl over time. Leaves lashes fully luxurious and soft while allowing the pigment of your favorite mascara to stand out thus creating an intense and rich false lash look. It can also be worn overnight as a "lash mask" to nourish and rejuvenate lashes overnight.