AR refers to parts or units that were removed from an aircraft and are now listed for sale. These could state a reason or occasionally be unrepairable after the product’s life.
FN - Factory New
FN indicates the condition of a product that is brand new from the factory. For it to be FN, the product should not be more than two years old since manufacturing.
IN - Inspected
IN code is used for parts that have been inspected for basic requirements along with different checklists of maintenance inspection if stated alongside.
