The 031-80107: It ships as a 5-piece kit — connector body, centre contact, ferrule, PTFE insulator, and a separate sleeve — so you don't have to source the dielectric and ferrule as line items. The 75 Ohm impedance and 4 GHz frequency ceiling match the standard 75 Ohm BNC interface. The PTFE dielectric keeps insertion loss to 0.2 dB across the band, and the gold-plated brass centre contact handles the 500-cycle mating life.
Cable compatibility — RG-179 family and Belden 9221
This plug is specced for RG-179, 179A, 179B, 187, 187A, Belden 9221, and M17/94-RG179 — all 75 Ohm, 0.100-inch-diameter class cables with a solid or stranded centre conductor around 0.025-inch. The crimp ferrule and centre contact are sized for that cable OD; using a different cable gauge means the ferrule won't compress evenly and the impedance step at the termination will exceed the 0.2 dB insertion loss budget.
500-cycle mating life — gold on the centre contact
The 500-cycle rating comes from the gold-plated brass centre contact mated against a phosphor bronze receptacle. Gold on the pin, nickel on the body — the body finish doesn't participate in the signal path, so the 500 cycles are real reconnect duty for field-service or test-rack use. The bayonet lock gives a positive mate without over-torquing, which is what wears out the plating on a threaded connector.