32 CFR § 2002.32
CUI cover sheets
July 1, 2020
(a) Agencies may use cover sheets for CUI. If an agency chooses to use cover sheets, it must use CUI EA-approved cover sheets, which agencies can find on the CUI Registry.
(b) Agencies may use cover sheets to identify CUI, alert observers that CUI is present from a distance, and serve as a shield to protect the attached CUI from inadvertent disclosure.