D38999/26FD19SN is a MIL-DTL-38999 Series III subminiature connector featuring a straight plug configuration with environmentally sealed design for harsh environment applications. The connector employs a threaded 360° turn coupling mechanism and is available with 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 maximum signal contacts using AS39029 contact types in crimp, solder cup/eyelet, or PCB tail styles, with shell sizes ranging from 9 to 25 and contact sizes of 23, 22, 20, 16, 12, 10, and 8. The connector operates across a temperature range of -65°C to +200°C (depending on shell finish), provides scoop-proof and EMI control features with spring fingers, and offers 500 mating cycles durability with higher durability versions available. These connectors are widely used in aerospace, defense, and marine systems where environmental sealing, reliability, and rugged performance are essential.