olemus
madalaim turvaklass, ei tarvitse aga tähendada avalikku teavet,
võib olla kitsendusmärgendiga, näiteks
"sensitive but unclassified" ("tundlik, kuid turvamääranguta") või
"for official use only" ("ametialaseks kasutamiseks")
CNSSI 4009-2015:
Information that does not require safeguarding or dissemination controls pursuant to Executive Order (E.O.) 13556 (Controlled Unclassified Information) and has not been determined to require protection against unauthorized disclosure pursuant to E.O. 13526 (Classified National Security Information), or any predecessor or successor Order, or the Atomic Energy Act of 1954, as amended. See controlled unclassified information (CUI), and classified national security information.

märgistus
NATO: tähed NU - ametlik teave, mis on NATO omand
USA: täht U, värvikood roheline

ülevaateid
https://dodprocurementtoolbox.com/cms/sites/default/files/resources/2017-06/Navigating%20Unclassified%20Information%20System%20Security%20Protections.pdf
https://en.wikipedia.org/wiki/Sensitive_but_unclassified
https://en.wikipedia.org/wiki/Classified_information