The Matrix Dark Envy Shampoo & Conditioner duo in 33.8 fl.oz sizes is a set designed specifically for those with dark hair, particularly brunettes or those with color-treated dark hair. This duo is formulated to enhance and maintain the richness and depth of dark hair colors while also providing nourishment and hydration to keep the hair healthy and vibrant. The shampoo works to cleanse the hair without stripping away color, while the conditioner helps to detangle, soften, and add shine. If you're looking to maintain the intensity and vibrancy of your dark hair color, this duo could be a great choice for you.