Amen I ON Nails Nail Hardener Treatment 0.40 oz use twice a week for amazing results great base coat or over nail color when needed for longer and harder nails and now with even more calcium. Improves nail growth and helps prevent chipping breaking from being brittle and weak. Calcium is the structural mineral component of nails so it brings more to help maintain the strength of nails. Use as a base coat top coat or Natural Nail treatment use twice a week for best results. Dali