Review (2/5): Don't waste your money
The effect is a great idea and works alright.
But the nail polish is muddy grey and really thin. Even with 3 coats it appears streaky and not consistent.
At best this may work over a darker nail polish but its just going to be covering it up with a nearly constant streaked black and grey appearance.
I don't recommend this product i'm sure there are better brands with the same effect in higher quality polish. Save your money!