Each station in an adjustment must have a unique station code. This is used to identify the station in other data files. The code can be up to 15 characters long, and can contain numbers, letters, and other characters. Codes cannot contain blank characters. and should not contain exclamation marks or hyphens. It is recommended that only numbers, letters, and the underscore _ are used in codes. It is recommended that station codes be no more than 5 characters long, as this ensures that the SNAP output file is no more than 80 characters wide (which makes it easier to view and print).