PCL Airflow Couplings and Standard Adaptors PCL Airflow Couplings and Standard Adaptors are robust, hard-wearing, and suitable for a variety of applications, particularly automotive (garage) facilities. The couplings and adaptors are interchangeable with RECTUS 19 series (part of the Parker Quick Coupling Division Europe [QCDE] range). The products are manufactured from steel, and incorporate a Nitrile rubber seal.