The 31-221: It's the fixed half of a standard BNC quick-connect pair — mates with any male BNC plug using the bayonet lock. The extended PTFE insulation and 500 V rating push this beyond a typical 50 Ohm signal connector; it's sized for applications where voltage standoff matters as much as signal integrity, like test equipment panels, RF distribution boxes, or broadcast gear where a 4 GHz passband is enough headroom.
What Ships in the Box and How It Mounts
No separate hardware order needed for a standard panel install. The bulkhead flange seats against the outside of the panel; the lockwasher and nut tighten from the rear side. That means you need rear-panel access for assembly, but the nut provides solid mechanical retention and a ground bond through the nickel-plated brass body.
Termination and Contact Construction
The silver plating on the center contact keeps solderability clean and contact resistance low over 500 mating cycles. Beryllium copper gives the socket fingers enough spring memory to hold grip through those 500 cycles without taking a set.