Satin Oxide Developers are silicone enhanced to provide optimal shine and conditioning during any chemical service. Use the Satin Developer that best fits your hair, mix with Satin Color into a rich, creamy, stay-put application. The silicone base in the Satin Developer provides a color-protecting barrier on the hair fiber, resulting in a much longer retention of color. Developer comes in 10 Volume, 20 Volume, 30 Volume and 40 Volume. Choosing A Developer: · 10 Volume is used when coloring tone on tone or darker. · 20 Volume is used when coloring tone on tone or up to 2 levels lighter. · 30 Volume is used when coloring up to 3 levels lighter. · 40 Volume is used when coloring up to 4 levels lighter.