This Costco-exclusive combo pairs the Olaplex No.4 Fine Bond Maintenance Shampoo with the Olaplex No.5 Fine Bond Maintenance Conditioner, each in a 250 mL (8.5 fl oz) bottle. Both products are formulated specifically for fine and fragile hair using Olaplex's patented bond-building technology, which works at the molecular level to repair broken disulfide bonds caused by chemical, thermal, and mechanical damage.

The No.4 Fine shampoo is a weightless, volumizing formula that cleanses while strengthening and repairing hair in a single wash. It adds body and shine without weighing fine strands down. The No.5 Fine conditioner delivers ultra-light moisture and detangling benefits, improving manageability and boosting shine while continuing the bond repair process initiated in the wash step.

Together, the duo helps strengthen, repair, and prevent future damage to fine hair, leaving it visibly healthier, fuller, and more resilient with regular use.