OLAPLEX Nº.1 BOND MULTIPLIER PRO REFILL is the professional first step of the in-salon system, designed to mitigate hair damage during chemical services such as coloring or lightening. This formula lessens damage during chemical processing by strengthening and protecting disulfide bonds inside the hair. It's formula provides damage prevention and repair treatment. It is designed to be added into chemical formulas like hair color, lighteners, permanent waves, and more.