These Cabin Pressure Relief and Isolation Valves are representative of a larger suite of components including manual and motor driven isolation valves, regulators, relief valves, pressure sensors, and flow restrictors.

The Quest Joint Airlock is a pressurized space station module consisting of two cylindrical chambers attached end-to-end by a connecting bulkhead and hatch. The airlock is the primary path for International Space Station spacewalk entry and departure for U.S. spacesuits, which are known as Extravehicular Mobility Units, or EMUs. Quest can also support the Russian Orlan spacesuit for spacewalks.

The Joint Airlock acts as a stowage area for spacewalk hardware as well as a staging area for crewmembers preparing to conduct a spacewalk. A combination of the depress pump and pressure equalization valves located within the hatches accommodate the depressurization/pressurization capability of the airlock.