It is an airtight, leakproof system that utilizes a membrane-to-membrane technology. It mechanically prohibits the transfer of environmental contaminants into the system and the escape of drug or vapor concentrations outside the system, thereby minimizing individual and environmental exposure to drug vapor aerosols and spills. It also prevents microbial ingress within an ISO Class V environment with proper aseptic technique. The BD PhaSeal system is a pioneer in the CSTD space. With more than 25 peer-reviewed, published studies, it is the most studied and according to a recent U.S. survey, BD offers the most widely used CSTD portfolio in the US.