- International Mail Manual > 2 Conditions for Mailing > 250 First-Class Package International Service > 254 Mail Preparation
First-Class Package International Service items are subject to the addressing requirements in 122.
The following markings apply to First-Class Package International Service items:
Unregistered First-Class Package International Service items may be sealed at the sender’s option. Mailpieces not sealed by conventional means, such as taping the open flaps for small packets, 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 Package International Service 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 package-size First-Class Package International Service items: