Want to protect your hair from damage while maintaining that enviable cool toned blonde? Let us introduce you to OLAPLEX's No 4P Blonde Enhancer Toning Shampoo. An update on the classic No 4 Bond Maintenance Shampoo, this new addition stars the same patented active ingredient that seeks out broken bonds in the hair (which are caused by chemical, thermal and mechanical damage) and repairs them, restoring compromised hair to former glory, but now with a purple toner to help keep warm toned hues from your precious hair.