46 CFR § 10.201 - General characteristics of the merchant mariner credential.
(a) A merchant mariner credential (MMC) (Coast Guard Form CG-4610), is a credential combining the elements of the merchant mariner's document (MMD), merchant mariner's license (license), and certificate of registry (COR) enumerated in 46 U.S.C. subtitle II part E as well as the STCW endorsement issued pursuant to the STCW Convention and STCW Code (incorporated by reference, see § 10.103 of this part). MMDs, licenses, STCW endorsements and CORs are no longer issued as separate documents and all qualifications formerly entered on those separate documents appear in the form of an endorsement(s) on an MMC.
(b) An MMC authorizes the holder to serve in any capacity endorsed thereon, or in any lower capacity in the same department, or in any capacity covered by a general endorsement.
(c) An MMC may be issued to qualified applicants by the Coast Guard.