The "Pepsi watch" has a red and blue bezel, which earned it its nickname, as the Pepsi logo uses the same color combination. The bicolor bezel has a practical use: The red half symbolizes day while blue represents night. One glance is enough to differentiate between night and day in the second time zone. The first GMT-Master II, introduced in 1985, featured a red and black bezel. Therefore, it's nicknamed the "Coke watch"..