Bain de Terre Naturage 1 Spa Conditioning Exothermic Perm. For normal/resistant hair and tinted hair (up to 20v). Low ammonia, self heating alkaline formula. Creates firm, resilient curl. Water wrap, process room temperature. Normal/resistant hair process 20 minutes. Test curl required for tinted hair – test after 5 minutes, then every 2 minutes. Max 12 minuted.