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, as well as RFI grounding plugs. Available in 9 shell sizes and 52 insert arrangements, they use M39029 rear release crimp contacts in various sizes, including coax and twinax. Constructed with high-strength aluminum shells, they offer plating options like light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum. RoHS-certified cadmium-free finishes are also available. Suitable for military applications, these connectors ensure reliable performance with features like gold contact plating, bayonet coupling, and a maximum operating temperature of 150 °C. The 19-35 shell size insert arrangement, along with a jam nut mounting receptacle design, makes them ideal for demanding environments that require conductivity and environmental resistance.