Hi
You define a security rule element by specifying a value range that includes both a low and high value for your segment. A security rule element applies to all segment values included in the value range you specify.
You identify each security rule element as either Include or Exclude where Include includes all values in the specified range and Exclude excludes all values in the specified range. Every rule must have at least one Include rule element since a rule automatically excludes all values unless you specifically include them. Exclude rule elements override Include rule elements.
You should always include any default values you use in your segments or dependent value sets. If the default value is secured the flexfield window erases it from the segment as the window opens and the user must enter a value manually.
-Thanks alot