This read-only string reports a second, additional ACL or filter identifier returned by RADIUS for this session, used when a user's access policy requires more than one filter attribute to fully describe. An administrator checks this alongside the first filter ID field to see the complete set of access restrictions RADIUS applied to a given authenticated session. For example, a session using both a base network filter and a supplemental time-of-day filter would show that second filter's name in this OID.