Pnuematic FRL have 3 basic functions: the filter cleans the air, the regulator sets the pressure, and the lubricator adds lubricant to the pneumatic system. SMC offers a complete FRL combination unit (Series AC) as well as offers each component (filter, regulator, lubricator) in a modular fashion. This Pnuematic FRL series is unique in that the FRL component bodies are threaded. This threading gives you the ability to use each component individually or as an assembled unit. In instances where the designs are more focused on FRL assembly, piping adapters can be used to connect the bodies. The connectors for this series are very thin; thus reducing the footprint.