MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, offering environmental sealing and a wide operating temperature range from -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, these connectors use M39029 rear release crimp contacts in various sizes, including coax and twinax options. Constructed with high strength aluminum shells, they come in multiple plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum. Additionally, they are available in RoHS certified cadmium-free finishes, ensuring compliance with environmental regulations.