OLAPLEX N°.7 Bonding Oil is the first-of-its-kind. Highly concentrated, ultra-lightweight, reparative styling oil dramatically increases shine, adds softness and strength, and enhances all hair types and textures. When used with any thermal styling appliance N°.7 provides heat protection up to 450°F/230°C. How To Use Remove cap. Invert bottle and gently tap index finger on the bottom to dispense a metered drop. Apply a small amount to damp or dry hair, style as desired. How much you use depends on hair length and texture.