49 CFR § 173.25 - LII / Legal Information Institute (a) Authorized packages containing hazardous materials may be offered for transportation in an overpack as defined in § 171.8 of this subchapter, if all of the following conditions are met: (1) The package meets the requirements of §§ 173.21 and 173.24 of this subchapter. (2) The overpack is marked with the proper shipping name and identification number, when applicable, and is labeled as ...