A leaktight enclosure designed to protect operators from hazardous/potent processes or protect processes from people or detrimental external environments or both. A basic enclosure consists of a shell, viewing window, glove/sleeve assemblies, supply and exhaust filters, light (s), gauge (s), Input and Output openings (equipment door airlocks, Rapid Transfer Ports (RTPs), etc.), and various other penetrations. There are two types of isolators:1.Closed Isolators – Isolators operated as closed systems do not exchange unfiltered air or contaminants with adjacent environments. Their ability to operate without personnel access to the critical zone makes isolators capable of levels of separation between the internal and external environment unattainable with other technologies. Because the effectiveness of this separation, closed isolators are ideally suited for application in the preparation of sterile and/or toxic material. Aseptic and Containment isolators are two types of closed isolators.2.Open Isolators – Open isolators differ from closed isolators in that they are designed to allow for the continuous or semi-continuous egress of materials during operation, while maintaining a level of protection over the internal environment. Open isolators are decontaminated while closed, and then opened during manufacturing. Open isolators typically are used for the aseptic filling of finished pharmaceuticals.NOTE: Containment, barrier isolation and isolation all refer to the same technology, which is enclosing an environment. In the interest of clarifying the existing confusion between the terms “isolators” and “barriers”, and providing authoritative implementation and validation of isolation technology, the Parenteral Drug Association (PDA) published in October 2000 the Draft for Technical Report No. 34 “Design and Validation of Isolator Systems for the Manufacturing and Testing of Health Care Products”.