What is the smallest size of envelope that should be used for correspondence?

The smallest size of envelope that should be used for correspondence is 3.5" x 5". This size is acceptable for official correspondence as it provides adequate space to include standard-sized letters or documents while still being compact. Correspondence in the Marine Corps often adheres to certain standards and guidelines to ensure professionalism and clarity in communication. The 3.5" x 5" envelope is useful for notes, smaller documents, or brief messages that do not require a larger format.

Envelopes smaller than this size, such as 3" x 4", may not be appropriate for sending formal correspondence, as they limit the type and size of documents that can be included, potentially affecting the professional appearance and readability. Similarly, the other larger envelope sizes, while suitable for correspondence, exceed the necessary minimum and may not be as efficient for simpler communications. The 3.5" x 5" envelope strikes a balance between size and functionality, making it the correct choice.