This product advertises itself as a bleaching kit that works in half the time. I have very black hair (asian) and I bought it to lighten my hair so that I could dye it a strong red color (Garnier Nutresse #66 Pomegranite).
It took me about 45 minutes for it to lighten my hair to a medium orange/brown color. I haven't bleached my hair in a while so I don't know if this is quick, but I do know that my hair is pretty resistant to tampering. I didn't mind the wait.
If you didn't know, the black in asian hair is not a very dark brown, but actually a very dark red. So when you lighten it, it becomes orangy.