The Postal Pneumatic Tube System in the USA was used in the following cities:

• Boston
• Brooklyn
• Chicago
• New York
• Philadelphia
• Saint Louis

United States Model Post Office 
Panama-Pacific International Exposition San Francisco 1915

American Pneumatic Service Co. Boston, Massachusetts.
Standard 8 inch and 10 inch carriers used to carry US Mail in Pneumatic Tubes between the Post Offices.

These receptacles carry 20,000,000 letters daily through underground Pneumatic Tubes in Boston, Brooklyn, Chicago, New York, Philadelphia, St. Louis.
Address this card, drop it on the moving belt and watch the work of the Conveyor System installed by the Lamson Company, Boston, Massachusetts.

At the back side:

Use ink in addressing letters or other mail matter.
Write plainly the name of the person addressed, street and number, post office and State.
Place your name and address in the upper left hand corner of the envelope or package so that if the letter or other piece of mail matter is not delivered it will be returned to you.
More than thirteen million pieces of mail matter were sent to the Division of Dead Letters last year because of carelessness in writing addresses.