What It Is Acidic Bonding Concentrate Leave In Conditioner is Step 4 of Redken's most concentrated system ever. This leave in conditioner helps repair strength and recondition hair while reinforcing weakened bonds even in the most processed hair. ヘ A little goes a long way! This product is lightweight but creamy in consistency and will coat your hair with less product than your average treatment. What It Does •Bonding Care Complex helps to repair strength and recondition weakened hair while reinforcing weakened bonds. •Silicones and fatty alcohols provide conditioning and add shine. •This leave in conditioner helps rebalance natural pH levels in hair to promote healthy hair regrowth.