• The K18 works at the innermost layer of hair, reconnecting polypeptide chains and disulfide bonds broken during bleaching, chemical services, and through heat damage. By addressing these damage sites at the innermost layer of hair, core strength and elasticity are renewed for strong, smooth, bouncy hair even after the most extreme damage done in the salon or home services. It works within 4 minutes of application. Hair feels renewed after use. This is a professional product (Great deal) and each purchase comes with a free gift. 🎁