All domestic outer mailers returned to the Fairfax County Office of Elections contain a turquoise colored band along the left-hand side.
However, in this image, please note the different colored stripes printed on the front of the mailer at the upper edge in the center. These are circled in red.
The color of this stripe indicates the Congressional District (CD) in which the voter resides.
These different colored stripes serve as a valuable sorting tool to ensure that ballots from the same CDs are kept together during preprocessing operations.