MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, designed for harsh environments with operating temperatures ranging from -65 °C to 200 °C. This connector family includes front wall mount, rear wall mount, and jam nut receptacles, and RFI grounding plugs, offering versatility. Available in 9 shell sizes and 52 insert arrangements, they use M39029 rear release crimp contacts in various sizes. Constructed with high-strength aluminum shells, they come with plating options like light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with some RoHS certified finishes available. Suitable for military applications, these connectors provide reliable performance with features like bayonet coupling, gold contact plating, and N keyway polarization. With a service rating of I and environmental resistance, they are ideal for demanding settings requiring durable and efficient electrical connections.