The 212984-4 is a 28-position plug insert designed for the ECMSC (Engine Control Module Sealed Connector) system. This component is manufactured from VALOX material. It is specifically identified by its 'FOUR' key ID, which provides a unique keying arrangement to ensure proper mating and prevent incorrect connections within a wiring harness. This plug insert is part of a series of keyed components intended for use in applications requiring secure and reliable connections, such as in automotive or industrial electronics.