MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, offering environmental sealing and a wide operating temperature range of -65 °C to 200 °C. This harsh environment 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 utilize M39029 rear release crimp contacts in various sizes, including coax and twinax options. Constructed with high-strength aluminum shells, these connectors come with plating choices like light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, offering versatility in applications. RoHS certified cadmium-free finishes are also part of the selection, ensuring compliance with environmental regulations.