Wella Koleston Perfect 9/7 Light Blonde Permanent Hair Color Light Blonde Wella Koleston perfect is one among the hair colors wit ME+ technology. This offers pure, balanced colour results with natural depth and shine. The unique characteristic of ME+ technology is that it is very likely to develop any allergy to the client. It has over 110 shades of intense vibrant color. Offers long lasting grey coverage and up to 5 levels of lift. Simple 1:1 mixing ratio. *This is a professional product and should be used only by a trained individual.