OPI Repair Mode Bond Building Nail Serum uses patented Ulti-Plex Technology™ which helps to strengthen and repairs nail keratin structure by penetrating the surface to build new bonds INSIDE the natural nail. This breakthrough nail treatment completely reprograms your nails, resulting in 99% nail keratin repair.* Nails look improved after the first application, and with continued use, you can expect smoother, stronger nails that are resistant to breakage and an improved appearance of ridges and colour.