MIL-DTL-38999 Series I connectors feature up to 128 contacts in an environmentally sealed insert, designed for harsh environments with an operating temperature range of -65 °C to 200 °C. This connector family includes front wall mount, rear wall mount, and jam nut receptacles, along with RFI grounding plugs. With 9 shell sizes and 52 insert arrangements available, they use M39029 rear release crimp contacts in various sizes, including coax and twinax. Constructed with high strength aluminum shells, they offer plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with RoHS certified cadmium-free finishes. Suitable for military applications, these connectors ensure reliable performance in demanding conditions.