Mailing Standards of the United States Postal Service - International Mail Manual > 2 Conditions for Mailing > 240 First-Class Mail International > 244 Mail Preparation
First-Class Mail International items are subject to the addressing requirements in 122.
The following markings apply to First-Class Mail International items:
- First-Class Mail International postcards, letters, and large envelopes (flats) must be marked “AIRMAIL/PAR AVION” or have PS Label 19-A, Par Avion Airmail, or PS Label 19-B, Par Avion Airmail, affixed to the address side of the mailpiece.
- First-Class Mail International letters and large envelopes (flats) that qualify as Free Matter for the Blind must bear the marking “Free Matter for the Blind” in the upper-right corner of the address side of the mailpiece. See 274.2.
Unregistered First-Class Mail International items may be sealed at the sender’s option. Mailpieces not sealed by conventional means, such as moistening the gummed flaps on envelopes, must be closed in such a manner as to prevent the contents from falling out or being damaged during postal handling and transport. First–Class Mail International items that use Registered Mail service must be sealed. (See 334.4 for sealing requirements for Registered Mail service.)
The following standards apply for packaging letter-size and flat-size First-Class Mail International items:
- Mailers must package mailpieces to withstand normal transit and handling without content or package breakage, injury to Postal Service employees, or damage to other mail or Postal Service equipment.
- Mailers must package their contents to prevent their deterioration.
- Mail matter is admissible in envelopes, sleeves, or wrappers of varying sizes and thickness
Note: Transparent plastic packaging is acceptable for international mailing purposes.
- Except as provided in 292.4 and 293.4, folded mailpieces, without envelopes, are admissible provided that all of the open sides are secured with glue, tape, tabs, or wafer seals of sufficient quantity and strength to prevent the mailpieces from opening or being damaged during postal handling.
- First-Class Mail International items in card form are permitted, so long as their overall dimensions do not exceed 4-3/4 inches high or
9-1/4 inches long (see 241.221).