The TE Connectivity 2061981-3 is a panel mount frame from the FullAXS Mini series, designed to secure and seal LC duplex connectors through a bulkhead or enclosure wall. It ships as a complete assembly that includes the bulkhead nut, O-ring, and sealing gasket — so you are not sourcing those separately for a weatherproof or dust-resistant feed-through.
What is really failing here? Most of the time it is not the frame itself — it is the O-ring getting pinched during reassembly or the seal drying out after years in a hot cabinet. This frame comes with both the O-ring and the seal in the box, so if you are replacing a leaky or corroded panel feed-through, you get fresh sealing hardware with the swap. The bulkhead nut threads onto the frame from the outside of the panel, and the O-ring seats against the panel face. No special tooling needed — a standard spanner on the nut is all it takes to fit it on site.
The frame accepts LC duplex connectors only — not simplex, not SC, not ST. If your existing harness terminates in a duplex LC, this frame crosses into it directly. The FullAXS Mini series is TE's compact outdoor-rated connector system for fibre optic terminations in harsh environments, and this frame is the panel-mount half that gives the connector a sealed, vibration-resistant anchor point.