All Cardinal Marks are horizontally banded yellow and black and have black cone shaped topmarks. During daylight hours, the band colors, and topmarks are used to identify which cardinal mark you are observing.

• Topmarks are always black.
• North Cardinal Mark (both topmarks pointing up) Black band above yellow band.
• South Cardinal Mark (both topmarks pointing down) Black band below yellow band.
• East Cardinal Mark (topmarks pointing away from each other) Black band above and below yellow band.
• West Cardinal Mark (topmarks pointing towards each other) Black band between yellow bands.

Cardinal marks have black and yellow bands with black double cones on top showing the different compass direction that identifies the safest and deepest water to travel in. At night, each type of cardinal mark has a flashing white light with different groupings of flashes