Isolators serve as an enclosure for aseptic processes (filling, loading and unloading of freeze dryers). Product protection is achieved by a barrier (manipulation unit and plenum) which separates the operator and the product. HEPA filtered unidirectional airflow provides Grade A conditions preventing particle swirl. Products and materials are transferred into and out of an isolator via transfer systems. All safety and GMP relevant functions should be permanently monitored and archived electronically.