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2-5 Envelopes

2-5.1 Use

Envelopes are acceptable for mailing certain items that can reasonably be expected to be processed and delivered without damage to the contents or to other mail or mail processing equipment.

2-5.2 Letter-Style Envelopes

A letter-style envelope is any nongusseted envelope within the dimensions shown in Exhibit 2-5.2. A letter envelope is acceptable for mailing nonrigid stationery and similar items weighing up to 1 pound and measuring up to
1 inch thick.

Exhibit 2-5.2

2-5.3 Other Envelope Styles

For an easy load of up to 5 pounds, an envelope that exceeds the letter-size dimensions is acceptable for mailing. This large envelope should be made from paper of at least 28-pound basis weight or from material with a Mullen strength greater than 90 pounds per square inch.

An envelope designed as a photographic film mailer or a gusseted envelope is also acceptable for mailing if it is made from envelope paper of at least 24-pound basis weight.

2-5.4 Odd-Shaped Items

Pens, bottle caps, and similar odd-shaped items are not acceptable in a letter-sized envelope mailed at the single-piece First-Class Mail rate. These items can split or burst the envelope and injure Postal Service employees or damage other mail and mail processing equipment.

An envelope may be used to mail an odd-shaped item at the bulk Standard Mail rate if the item meets the requirements for that mail class. The item should be wrapped with the other contents of the envelope to streamline the shape of the envelope for automated processing. The item's package should be able to effectively hold it so that the contents and the package will not be damaged.