MIL-DTL-38999 Series I connectors are designed for harsh environments, featuring up to 128 contacts in an insert with environmental sealing. Operating between -65 °C and 200 °C, these connectors offer front wall mount, rear wall mount, and jam nut receptacles with RFI grounding plugs. 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 in plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, including RoHS certified cadmium-free finishes. Suitable for military applications, these connectors ensure reliable performance with gold contact plating, a maximum operating temperature of 150 °C, and a service rating of M. With a service class detail of Environment Resistant Wall and Jam Nut Mounting Receptacle and Plug Types, they offer a durable and conductive solution for demanding connectivity needs.