Final answer:
The Ultra.Blonde series is suitable for natural hair that is at a level 6 or higher on the hair color scale.
Step-by-step explanation:
The Ultra.Blonde series of hair products is designed specifically for lightening natural hair to a very light blonde shade. This series is typically used on hair that is already at a level 6 or higher on the hair color scale.
The hair color scale ranges from level 1 (black) to level 10 (palest blonde). To determine the level of your natural hair, you can assess the darkness or lightness of your hair color.
If your hair is already at a level 6 or higher, you can use the Ultra.Blonde series to achieve a lighter blonde shade. However, if your hair is darker than a level 6, you may need to first lighten your hair using a separate hair lightening product before using the Ultra.Blonde series.