Longest Night is a black holographic polish, and is opaque in approximately two coats.  To make this a black holo polish (instead of a grey), the opacity of the black is such that it does somewhat reduce the holographic effect.  This is still a linear holographic polish, but it isn't as strong as the majority of the Winter Holodays collection.  Longest Night is named for the winter solstice, the longest night of the year.  A base coat is recommended with this polish, as it is highly pigmented and highly pigmented polishes can stain. 

Rather than offering sets, purchasing three or more bottles of polish from the Winter Holodays collection in a single order will give a discount of 3.5% on all Winter Holodays collection polishes in the order, which will be reflected in the cart under the line "Winter Holodays collection discount."

The last photo shows what Starlight Polish 15mL and 7.5mL bottles look like.