The 5226978-3: The bayonet lock gives a fast, positive mate with the matching BNC plug; the coupling nut snaps into place with a quarter-turn and the detent holds it against casual vibration.
Rated to 4 GHz, the 5226978-3 covers the full BNC band for instrumentation, test equipment, and low-power RF up to the UHF spectrum.
The shell is zinc with a nickel body finish — the nickel provides a hard, corrosion-resistant surface that also gives a consistent ground path through the mating interface. The housing colour is listed as natural and silver, reflecting the nickel finish. The isolated feature designation means the connector body is not internally tied to the centre conductor — standard for a jack where the shield is separate from the signal path.