Which manual or document would be used to find information on the maximum size standards for a machinable parcel?

The Domestic Mail Manual (DMM) is the comprehensive resource for regulations, procedures, and guidelines related to domestic mailing in the United States. It contains the maximum size standards and specifications for various mail types, including machinable parcels. This document serves as a reference for understanding the criteria that a parcel must meet to qualify for machinable status, which is important for ensuring the efficient processing and deliverability of mail.

The other documents mentioned, while useful for specific purposes, do not focus on size standards for machinable parcels as comprehensively as the Domestic Mail Manual. For instance, the Postal Service Handbook provides policies and procedures but may not include specific details on size limitations. The Mailing Standards Manual covers a wide range of mailing requirements but is not the primary document for size standards. The Parcel Service Guide may offer additional insights into parcels but lacks the definitive size criteria found in the DMM. Thus, the Domestic Mail Manual is the most authoritative and relevant source for this information.