Link-D BOND SEALER N°4 is a serum for the hair for professional and home use. It creates a protective barrier on the hair’s cuticles, which is capable of maintaining moisture and prolonging the repairing effect on the disulphide bridges created by the previous Link-D steps. It gives hair gloss and protects its shine by acting as a UV filter whilst it also: - Reconstructs the hair fibre - Protects the hair - Restores strength to the hair from technical services done in the salon