Base military stores or Exchanges are commonly called a Base Exchange (BX) on U.S. Air Force installations, and they are referred to as a Post Exchange (PX) in the U.S. Army. Exchanges on Army and Air Force installations are run by the Army and Air Force Exchange Service (AAFES). Every exchange operated by the AAFES has been rebranded simply as an Exchange to simplify differentiation between the similar sounding BX and PX names.

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