Da Vinci Creme Developer 40 Vol Unique creamy consistency assures easy blendability with Da Vinci color. 100% stabilized to ensure the highest quality results with accurate true to tone deposit. Da Vinci Creme Color must be used with stabilized hydrogen peroxide (Da Vinci Creme Developer) in a ratio of 1:1.5, i.e. 1 part coloring creme + 1 and 1/2 part oxidant (3oz of color + 4.5oz of peroxide) - enough for 2 complete applications on medium/long hair, or retouching 4 times. Use half tube creme hair color and 75ml peroxide Semi, 10, 20, 30, 40 volume depending on the need for lightening, highlighting and shading. Be aware that choice of the emulsifying developer is important to achieve desired result. Available in 20, 30, 40, Semi and Gray Eliminator (GE): 10 Volume Developer has no lightening effect 20 Volume Developer has 1 shade effect 30 Volume Developer has 2 shade effect 40 Volume Developer has 3 shade effect, but to go more than 4 shades lighter it is necessary to bleach the hair.