The Intelligent Mail Package Barcode (IMpb) provides the best commercial prices with the largest discount available, piece-level tracking information at no additional charge for most products, and access to new products, services, and enhanced features. The addition of two (2) supplemental IMmb’s to the existing IMpb on a USPS shipping label results in enhanced package visibility with less mail rework.

The Mailer Identifier (MID) is a field within the Intelligent Mail barcode that is used to identify mailers. MIDs are assigned by the USPS^® to a Mail Owner, Mailing Agent or other service providers who request them.

The USPS^® Customer Registration ID (CRID) is a unique number that identifies a specific business location involved in a mailing. In order to submit electronic documentation (and receive Full-Service benefits), customers must have a customer registration ID assigned to their business location. 

The Intelligent Mail barcode (IMb) is used to identify mailpiece movement through the postal system and support any additional services requested for that mailpiece. The STID defines the mailpiece as full-service or basic (non-automation) and is also used to determine the disposition of undeliverable-as-addressed (UAA) mail and the form of address correction that a mailer desires if any.