What This Coupling Ring Does in the Assembly
The TE Connectivity 213811-1 is a coupling nut for the CPC (Circular Plastic Connector) series, shell size 11. It threads onto the plug housing to lock the mated pair and compress the interfacial seal. The black nylon body gives it a light, corrosion-resistant shell that handles the torque of hand-tightening without galling against the connector threads. This is the ring that secures the cable-side half to the panel-mount receptacle in a CPC interconnect.
Shell Size and Material Fit
Shell size 11 is the standard insert dimension for CPC connectors in this class — it matches the coupling thread diameter of the corresponding plug and receptacle. The nylon material keeps the ring non-conductive and avoids the galvanic corrosion issues a metal ring would introduce in a mixed-material assembly. Black color is the standard finish for the CPC line; no secondary marking is needed for visual identification on the harness.