| The following procedures apply
    to mailing or carrying classified materials. These procedures cover the most
      common circumstances but do not cover the shipment of bulky materials. It
      is intended as general guidance only and is not a substitute for review of
      the official regulations. TOP SECRET material may not be
        sent through the mail under any circumstances. It must be transmitted by cleared courier
        or approved electronic means. SECRET material may be
        transmitted by U.S. Postal Service registered mail or express mail within and between the United States
        and its territories. However, the "Waiver of Signature and Indemnity" block on the Express Mail Label 11-B may not be executed, and the use of external
        (street side) express mail collection boxes is prohibited. SECRET
        material may be sent through U.S. Postal Service registered mail through
        Army, Navy, or Air Force Postal Service facilities outside the United States, provided
        that the information does not at any time pass out of U.S. citizen control and does not
        pass through a foreign postal system or any foreign inspection. Federal Express may also
        be used for SECRET material for urgent, overnight delivery only,
        but contractors must receive approval from their government contracting
        authority to use this method.  CONFIDENTIAL material is
        subject to the same mailing procedures as Secret material, with the
        following exceptions: 1) CONFIDENTIAL material may be sent by U.S.
        Certified mail rather than by U.S. Registered mail. 2) Government
        agencies (but not contractors) may also send CONFIDENTIAL material by
        First Class mail between and among government agencies only. It cannot
        be sent to contractors via First Class mail. Under all circumstances, the outer envelope should be
        marked "Do Not Forward. Return to Sender." Under no circumstances shall the USPS
        Express Mail label 11-B "Waiver of Signature and Indemnity" be used. Classified material must be
    mailed at the post office. Use of street mail collection boxes is prohibited. WrappingAll classified material must be
    double-wrapped with opaque inner and outer covers. It shall be marked as follows: 
      Mark the inner envelope top
        and bottom on both sides, preferably in red, with the classification in capital letters. A
        box with classified material should be marked with the classification on all surfaces of
        the inner wrapping. 
      On the outer envelope, write
        the complete mailing address and return address. Do
        not indicate on the outer envelope that it contains classified information.
        Classified mail or shipments should be addressed to the Commander or other head of the organization by title, not by
        name, or to an approved classified mailing address of a federal activity or to a cleared
        contractor using the name and classified mailing address of the facility. An
        individual's name should not appear on the outer envelope. Instead of a
        person's name, use office code letters, numbers, or phrases in an
        attention line to aid in internal routing. When necessary to direct
        material to the attention of a particular individual, put the
        individual's name on an attention line in the letter of transmittal or
        on the inner container or wrapper. For Official Use Only is a
    document control designation, not a
    classification. Such material may be mailed in a single envelope. ReceiptsA receipt identifying the
    sender, the addressee, and the document should be attached to or enclosed in the inner
    envelope as noted below. The receipt shall contain no classified information. 
    It should be signed and returned to the sender. Top Secret material must be
    transmitted under a continuous chain of receipts covering each individual who obtains
    custody. For Secret material, a
    classified material receipt must be included with all material transmitted outside the
    facility. For Confidential material, a
    receipt must be included only if the sender deems it necessary, or if the information is
    being transmitted to a foreign government. Hand-Carrying
    Classified MaterialFor hand-carrying classified material,
    different procedures apply for surface transportation, commercial air, government air, and
    for transportation outside the continental U.S. 
      
        | If you personally transport classified material by car
        or foot to another location, you must provide reasonable protection for the information
        under all foreseeable contingencies that might occur while in transit. Automobile accident, theft and sudden illness are all
        foreseeable contingencies. This means the classified information must be double wrapped or
        packaged as though it were being sent by mail, kept under your constant control (i.e., not
        left in the trunk of your car while you run another errand), and delivered only to an
        authorized person. A briefcase may serve as the outer wrapper only if it is
          locked and approved for carrying classified material. Prepare an inventory of the material and leave
          one copy in your office and another copy with a security officer or
          other responsible person.
           |  | 
 Carrying
        classified material on trips that involve an overnight stopover is not permitted without
        advance arrangements for overnight storage in a U.S. Government office or a cleared
        contractor facility. |  |