An extremely useful set of cards which makes a difficult subject much easier. Each card shows a vessel's display of night-time navigation lights (in colour) or daytime shapes, as seen from your position. In the case of the cards showing lights the vessel's silhouette is just discernible. The meaning is shown on the back of the cards as usual. Learning the lights and shapes is a major part of a mariner's study and Flashcards make it much easier to master. There are over 50 cards in the set. Presented in a clear plastic hard case.