The MIL-DTL-38999 Series II connectors are designed for harsh environments, featuring up to 128 contacts within an insert. These environmentally sealed connectors have a wide operating temperature range from -65 °C to 200 °C, making them suitable for various applications. Available in nine shell sizes and 52 insert arrangements, they offer versatility in connectivity. The connectors come in aluminum shells with options for plating, including light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, meeting military specifications. With front and rear wall mount, jam nut, and box mount receptacles, as well as straight and 90-degree cable clamp plugs, they provide flexibility in installation. Utilizing M39029 rear release crimp contacts, these connectors ensure reliable performance in demanding conditions.