Product Description Strengthens weak nails. Hardens nails prone to breaking. Strong Hardener is a treatment polish to strengthen weak nails which are easily broken. For an intensive treatment, apply daily for 3 weeks. Remove the color polish completely every 3 days and repeat the process. HOW TO USE Apply as a base before nail polish. For an intensive treatment, apply daily for 3 weeks. Remove the color polish completely every 3 days and repeat the process.