Whether cover plug, protective cap or skin top, the black protective plug is for protecting unused M12 plugs on operating devices or cables so that they do not become dirty or come into contact with moisture. https://elecena.pl/product/24062247/200200-06-accesories 2023-08-22 https://elecena.pl/product/24062247/200200-06-accesories 2025-11-28