The body is nickel-plated zinc, and the dielectric is polymethylpentene (PMP). This sits in the standard TE BNC line, defined by the base number 227222.
The 4 GHz upper frequency limit tells you the usable bandwidth; beyond that, the VSWR rises and the signal degrades. The 500 mating cycles is a solid durability figure for a bayonet-lock connector — it handles field-service reconnects and test-bench use without the center contact wearing through its gold plating. The solder termination on the shield and center contact means you terminate the coax cable directly, not through a crimp — a clean solder joint is critical to maintain the 50 Ohm path through the transition.
Panel-mount jack with a bulkhead feature — the front-side nut clamps it to the panel.