Description Mavala Scientifique K+ Nail Hardener 5 ml allows split, soft or brittle nails to quickly regain a normal appearance, becoming strong and shiny. Its formaldehyde-free formula hardens the nail plate by sealing the three layers of the nail together. It penetrates quickly for immediate action. Its formula works thanks to a scientifically formulated active ingredient that improves the cohesion of keratin fibers, thus sealing the three main layers of the nail together. It also contains crystalline resin tears from the mastic tree, a gum extract that contributes to the natural keratinization process of the nail. The nails are hard, beautiful and ready to be enhanced.