CATALYST 25 and 35 are special "liquid developers" -  created to be used with the Natural Choice Colors system. Their formula is enriched with Aminoacids and pure Collagene for the protection of hair and skin during laying times.   They develop the pigmentation and  regulate the potentialities of lifting and coverage of gray hair. This is a specific volumetric system for developing special reflexes and for gray hair coverage on particularly difficult and refractory hair.   Enriched with protective substances, shiners and detanglers. During the colouring treatment the CATALYST balances the pH and protects scalp during the whole laying time. You will obtain a homogeneous gel that doesn't drop during the service.   25 volumes - strenghtens gray hair coverage 35 volumes - for lifting and deeper red tones