Its both, i just rang them up and explained, posted my mirror and they found the closest possible match.

Kit comes with base coat, although you can getyour own but colours alter after effect.
The actualy candy is like a dye thats mixed into the laquear and applied in at least 3coats, the more coats, the darker the result, then you put 2 coats of clear coat on top once candy applied.

I just bought the full kit off them so there was no excuse for cock ups, its not cheap though but still considering its actually reasonably priced for what it is