Remember that the female ferrule goes with the male MC4 connector, and the male ferrule goes with the female MC4 connector. Connectors come in many different AWG sizes. Be sure to get the correct size for the PV cable you are using. If you have to buy extra connectors, be sure to get them from the same manufacture as sometimes the end cap may be slightly smaller, and you will have a hard time getting them onto the cable. Enjoy!

Thanks for the explanation !

well explained