1. Any item of supply that is available in the commercial marketplace; or 2. Any previously developed item of supply that is in use by a department or agency of the United States, a state or local government, or a foreign government with which the United States has a mutual defense cooperation agreement; or 3. Any item of supply described in definition 1 or 2, above, that requires only minor modification in order to meet the requirements of the procuring agency; or 4. Any item of supply that is currently being produced that does not meet the requirements of definition 1, 2, or 3, above, solely because the item is not yet in use or is not yet available in the commercial marketplace.