Each card shows a vessel's display of night-time navigation lights in color or daytime shapes, as seen from your position. Packaged in a plastic envelope, these 2 1/2 x 3 1/2 inch flip cards help you study for exams. Similar to flash cards, there is a picture on one side and the description on the other. 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. This set has been a "best seller" for over 20 years because learning the lights and shapes is a major part of a mariner's study and without Flip Cards it's not easy. Each pack contains 50 cards. Dimensions: 2 1/2 x 3 1/2 '' Manufacturer: Flip Cards