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. Offering 9 shell sizes and 52 insert arrangements, they use M39029 rear release crimp contacts in various sizes, including coax and twinax. These connectors come in high strength aluminum shells with plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with RoHS certified cadmium-free finishes available. Suitable for military applications, the connectors are known for their durability and reliability, meeting stringent MIL-DTL-38999 I specifications.