For convenience, one could choose this Black Pearl Permanent Hair Dye Shampoo. At least once in a month, I will have to do some "repair" work to cover up my grey hair. It is annoying but I am grateful to have hair :D..Need not complain much because it is hereditary that I have grey hair from my grand mother.
I have tried this Black Pearl Permanent Hair Dye shampoo before. The dye does not last as permanent as it stated but I like it being convenient to use.