D38999/20WC8PN 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 and is available in stainless steel, aluminum, or composite shell materials with multiple plating options including electroless nickel, nickel PTFE, black zinc-nickel, and olive drab cadmium finishes. It supports up to 187 signal contacts with standard contact sizes of 8, 10, 12, 16, 20, 22, and 23, and offers contact styles including crimp, solder cup, eyelet, and PCB tail configurations. The connector operates across a wide temperature range of -65°C to +200°C (depending on shell finish), provides 500 mating cycles durability with higher durability versions available, and includes features such as scoop-proof design, EMI spring fingers, and hermetic/filter versions. Standard configurations include straight plugs with EMI spring fingers and lanyard release options, as well as receptacles with box mounting, wall mounting, jam nut, solder mount, weld mount, and through-hole bulkhead options, making it ideal for critical interconnect applications requiring environmental sealing and electromagnetic interference control.