Topic summary
Postal service
Extracted from the Wikipedia article Mail.
Other mail services
Packages are often sent through some postal services, usually requiring additional postage than an average letter or postcard. Many postal services have limitations as to what a package may or may not contain, usually placing limits or bans on perishable, hazardous or flammable materials. Some hazardous materials in limited quantities may be shipped with appropriate markings and packaging, like an ORM-D label. Additionally, as a result of terrorism concerns, the U.S. Postal Service subjects their packages to numerous security tests, often scanning or x-raying packages for materials that might be found in biological materials or mail bombs.