Cubs Win Flag
The flag has used two different colors with the letter "W" on a solid background.  The flag used now is white with a blue "W." There is a flag used for losses with a letter "L".  This flag is blue with a white "L" on it.  Additionally, lights are shone on the flags that show if it was a win or loss. A new flag is used for each win. Some stores sell versions of the flag that also have the Cubs logo at the bottom.