It is a panel-mount bulkhead connector with a bayonet lock, terminated via solder cup to the center contact.
Below 4 GHz, the BNC interface delivers a controlled impedance match — above that, the interface's inherent mode conversion and VSWR rise become unacceptable for most RF designs. The gold-plated center contact (phosphor bronze) keeps contact resistance stable over 500 mating cycles, which matters for field-service test points where the connector sees daily engagement.
Panel mount via bulkhead — front side nut secures the jack to the panel. The lockwasher prevents loosening under vibration. The shield is terminated via solder to the body, and the center contact is solder cup, so you hand-solder the coaxial cable's center conductor and braid. The body finish is nickel, which provides corrosion resistance and a consistent ground path.