The Viking ECUKEYC (often sold as ECUKEYC20) is a genuine OEM lock cylinder with two matching keys, designed for securing the ECU/control-panel cover on Viking G-5® swing-gate operators and later ECUNX/solar models (I-8, X-9). Installed in the ECU chassis, it ensures only authorized users can access internal settings, wiring, and electronics—maintaining safety and UL compliance. It's part #16 in Viking documentation and provides robust protection against tampering.