It's a single-port bulkhead-mount connector with a bayonet lock — the standard quick-connect interface for RF test equipment, instrumentation, and telecom gear up to 4 GHz.
The 50 Ohm impedance is the first thing to check — this jack is built for 50 Ohm coax (RG-58, RG-8X, LMR-195, etc.), not 75 Ohm video cable. Match it with a 50 Ohm plug and cable or the return loss takes a hit. The 4 GHz max frequency covers most bench RF, cellular, and Wi-Fi bands below that ceiling — above 4 GHz the interface geometry starts to limit performance. 500 mating cycles is standard for BNC; the bayonet lock wears gradually, but at 500 mates the centre contact and dielectric still hold the impedance tolerance for field-service life. The 500 V rating is the dielectric withstand between centre and outer conductor — adequate for the RF power levels typical of a 50 Ohm line at these frequencies.
Panel mount through the bulkhead, secured by a front-side nut — the jack body sits flush on the panel face, and the nut tightens from the front so the connector doesn't spin when you mate the cable.