The Kérastase Resistance Ciment Thermique is a heat-activated strengthening leave-in treatment designed to fortify and protect your hair from the damaging effects of heat styling tools. This innovative formula combines advanced technology with nourishing ingredients to provide thermal protection, strengthen weakened hair, and enhance its overall resilience. The 9-pack offers a convenient and cost-effective way to ensure your hair stays strong and healthy while styling. Heat Protection: This leave-in treatment forms a protective shield around your hair strands, minimizing damage caused by heat from styling tools like blow dryers and flat irons.