The general disadvantage is that the lead content is low and the fixation time is not long. If you are in a barber shop, because the color can be adjusted, if you want to dye a color, you'd better choose a lighter one. Of course, it depends on the texture of the hair. If the hair is black and hard, as I said, that's right.

I wonder what these two series of lz refer to?

According to my understanding, it's a silver-gray box and a golden box, right?

The silver-gray one has good gloss, but it can't cover the white hair.

Golden yellow dye will lack luster, but it has good coverage.

If you don't have white hair, you'd better choose silver gray. Those series of colors are more beautiful.

As for the color, it still depends on your skin color. If your skin is white, dye it in any color. Personally, I prefer chocolate color, which is low-key and fashionable. If you want to highlight a few strands of hair, it is also very beautiful.