What does 'first-class mail' refer to?

First-class mail refers to a category of mail that is prioritized for speed and reliability, typically including letters, postcards, and small packages. This service is designed for items that require quick delivery, usually within one to three business days depending on the distance being traveled. It is commonly used for personal correspondence, important documents, and bills due to its efficiency in reaching recipients promptly.

The focus on letters and small packages highlights the nature of first-class mail as an effective means for sending personal and lightweight items rather than bulk shipments or express services. Avoiding options related to slow delivery methods, international-only services, or exclusive express shipments reinforces the distinct characteristics that first-class mail embodies within postal services.