Paul Mitchell 40 Vol. Cream Developer 12% helps you achieve vibrant, long-lasting results using hair color or bleach. This professional-grade hair product is designed to activate hair color or bleach and help it penetrate the hair shaft for optimal results. The cream-based formula provides smooth and even coverage, making it an ideal choice for use with Paul Mitchell's hair color line. With a strength of 12% hydrogen peroxide, this developer is powerful enough to lighten dark hair or achieve a very light blonde result. However, it should be used with caution to avoid hair damage. The 33.8 oz (1 liter) bottle is a generous size and is intended for use by licensed cosmetologists. Ingredients include Cetearyl Alcohol, Lanolin Alcohol, Sodium Lauryl Sulfate, Salicylic Acid, and Phosphoric Acid. The active ingredient is 12% hydrogen peroxide. This product comes in creams form. Meant for unisex use. To use mix developer and with desired amount of hair color or bleach according to directions.