D38999/20WD97PN is a MIL-DTL-38999 Series III subminiature connector designed for rugged, harsh environment applications in aerospace, defense, and marine industries. The connector features a threaded 360° turn coupling mechanism with environmentally sealed construction, scoop-proof design, and optional hermetic and filter versions. It supports shell materials including stainless steel, aluminum, and composite, with multiple plating options such as electroless nickel, nickel PTFE, black zinc-nickel, and olive drab cadmium. The connector operates across a wide temperature range of -65°C to +200°C (depending on shell finish), accommodates up to 187 signal contacts with AS39029 contact type, and supports contact styles including crimp, solder cup/eyelet, and PCB tail configurations. With a standard durability rating of 500 mating cycles and available higher-durability versions, this connector is ideal for critical aerospace, defense, and marine systems requiring reliable, sealed electrical connections in demanding environments.