Toughen up your nails with the power of OPI Nail Envy Original Nail Strengthener Maximum Strength Formula. Weak, brittle nails need more than just manicures. OPI nail strengthener designed to help fortify weak, brittle, damaged nails. The custom-formulated blend is rich in calcium and hydrolyzed wheat protein to strengthen nail beds. The clear treatment is ideal to use between manicures. Nail Envy nail strengthener is easy to apply to clean, dry nails with OPI's signature wide brush. Each bottle contains .5 fl oz.