Natural nail strengthening treatment for nails by OPI | The strengthening basis of strengthening natural nails OPI gives nails strength and acts as a protective barrier between your natural nail and the color to prevent pigments and stains. Infused with Vitamins A and E, Natural Nail Strengthener with Wheat Protein and Calcium strengthens nails, helps prevent discoloration and repairs damaged nails. Use it alone or as a base under color to give more strength to your manicure. Advantages: | Vegan formula free from original ingredients or derivatives animale. Contains vitamin A and E.