A list of Clearance levels, their order, and corresponding security
Alpha - Public Domain
Beta - Enlisted Personell Only are allowed
Gamma - At least a tier two when applicable, if not, the second rank of the division can see this
Private - No registered personell, aside from superiors (inquiring about these things), the sender, and the addressee may view these
Zeta - Only High Command may see.
Omega - Highest level of security. Only the Owner, Seconds-in-Command, and What would be 'Thirds-in-Command' may view.