SO, onto the polishes themselves, first up is Mermaid Tail, which is a gorgeous deep teal-ish metallic green. I have painted both of these colours over a pale pink, so it's pretty close to how they'd be over my natural nails. This one definitely builds up quicker and is less sheer than most of the other Under the Sea polishes, with only two to three coats needed.
The second polish is Underworld, a shimmery blue metallic. This one is more sheer like the other polishes in the collection, and I used four to five coats for the below look. You can of course use less coats and make it a shimmery topper over another colour. I like the formula for both of these and they have the now classic Barry M wide flat brush which in my opinion is perfect! Mermaid Tail is my favourite as it's such a strong colour, but I think they are a good pair, and would recommend :) Great names too!