CRABS provide a physical and hermetic barrier between the operator and the product, ensuring a sterile environment by preventing contamination from airborne particles or microorganisms. These systems utilize HEPA-filtered unidirectional airflow to maintain an ISO 5 environment, with air recirculated through dedicated return ducts in a sealed chamber. The design allows for operation at different pressure differentials relative to the surrounding environment and includes monitoring and control of processing parameters such as velocity, pressure, temperature, and humidity.

ORABS, on the other hand, are designed to restrict access to critical areas while allowing for certain interventions without compromising the sterile environment. They typically feature unidirectional airflow and physical barriers but may permit limited openings for operator access under specific conditions. While oRABS offer a degree of contamination control, they may not provide the same level of containment as cRABS, which are fully enclosed systems.