In addition to the structural lock (primary lock) of the connector itself, to make the connection more stable, some accessories are usually required, Common ones are as follows:
CPA, Connector Position Assurance. It is a secondary locking that fixes the connectors. It can ensure that the male and female interfaces will not exit easily after being assembled in place. Due to its special function, CPA must ensure the operability and identifiability of workers in the design, which requires that CPA must be an independent mechanism on the plastic shell and have special color identification. In many cases, if the primary lock of the connector is relatively firm, CPA can be canceled, which is not necessary. Many people think that this is a necessary part which is incorrect. Only the housing of some vibration equipment needs to install it.TPA (terminal position assurance) is mainly used to fix the terminal position. Of course, the terminal can be fixed on the TPA slot and structurally fixed by TPA and connector. It can also be used as a stop after the terminal is inserted into the connector (the terminal structure itself often has primary locking and secondary locking). To ensure the convenient installation of workers in the harness factory, the color of TPA is also required to be recognizable, and there should be a clear hand feeling during assembly.
Not all terminals need a secondary locking structure. VW requires that TPA should be used when the terminal width is less than 2.8mm (including 2.8). To ensure that TPA will not automatically enter the locking position during the transportation of plastic shells to the harness factory, an anti-locking mechanism is necessary on TPA. 
| The Locking Clip is to fix the connector to the body assembly position. But we put this series of products in the Cable Ties & Fixing series, you can check them in that series. |  |
Auxiliary installation of male and female connectors. 
| Auxiliary installation of male and female connectors. |  |
