The MIL-DTL-38999 Series II connectors feature up to 128 contacts within an environmentally sealed insert, designed for harsh environments with an operating temperature range of -65 °C to 200 °C. These connectors come in various configurations including front and rear wall mount, jam nut, and box mount receptacles, along with straight, RFI grounding, and standard plugs. With 9 shell sizes and 52 insert arrangements available, they utilize M39029 rear release crimp contacts in sizes 22D, 22M, 22, 20, 16, and 12. Constructed with aluminum shells, they offer multiple plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, including RoHS compliant finishes. Ideal for military applications, these connectors provide reliable electrical connections in demanding conditions.