Mail pieces not meeting minimum criteria, or exceeding certain maximums are:

The correct response identifies mail pieces that do not conform to established postal regulations concerning size, weight, or other critical criteria as non-mailable. Non-mailable items are those that do not adhere to the specifications set forth by the USPS, which are essential for ensuring proper handling, processing, and delivery.

Non-mailable items typically include those that exceed weight limits, do not meet minimum size requirements, or consist of prohibited content. Understanding these limitations is crucial for anyone engaged in postal services, as it affects the overall efficiency of mail processing and delivery systems. Familiarity with what is classified as non-mailable helps postal workers to quickly identify issues that could prevent a mail piece from being successfully sent or delivered, ensuring that only compliant items are processed.