Flash Black is one of the polishes that I picked up recently. It is so unassuming in the bottle, but on the nails it looks gorgeous. I used two coats of polish, which I think is the same for all my Layla holographic polishes. On top I used Laylas's Nail Polish Sealer, a top coat kind of product, which is the only one I have ever tried that gives insane shine and doesn't dull the prismatic effect at all. Although it claims to prolong nail polish wear 'until you decide to remove your polish', it prolonged the wear for me on this polish by one day.