What it is: A serum that penetrates the skin to deeply nourish and hydrate cuticles while smoothing and strengthening nails without any oily residue.What it does: Its formula helps protect and harden keratin within nails with a blend of argan oil, vitamin E and apricot oil. How to use: With the soft precision brush applicator, dispense a drop of serum onto each finger and gently massage in. 0.33 oz.