[Trevally.]

Red ATONs always have even numbers, and green ATONs have odd numbers. Under the IALA B standard used in North and South America, when you are going to sea, the red ATON is on your left, and the green on your right. Under the IALA A standard used in Europe, Africa and most of Asia, the colors are reversed.
In the IALA B system, the red ATONs are on your right when you return from sea (Red Right Returning) and the green on your left. Red daybeacons are triangles and green daybeacons are squares. All of these ATONs are Lateral Markers that mark traffic channels and where it is safe to travel.