This product is a professional-grade hair color treatment from Tecna's Biorganic Acid Color line, presented as a multi-pack for extended use. Designed to deliver rich, lasting color results, this formulation emphasizes hair health during the coloring process. It is ideal for achieving the shade 4.0 Castano Medio (Medium Chestnut). Use this product when seeking reliable, salon-quality permanent or semi-permanent color application.