MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, designed for harsh environments with an operating temperature range of -65 °C to 200 °C. Available in various shell sizes and insert arrangements, they offer front wall mount, rear wall mount, and jam nut receptacles with RFI grounding plugs. These connectors use M39029 rear release crimp contacts in sizes 22D, 22M, 22, 20, 16, and 8, including coax and twinax options. Constructed with high-strength aluminum shells, they come in plating variations such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with RoHS-certified cadmium-free finishes. Suitable for military and industrial applications, these connectors are ideal for back panel box mounting with bayonet coupling and removable crimp contacts. With a service rating of I, they ensure reliable performance with 500 mating cycles and conductive properties, offering environment-resistant solutions for critical connectivity needs.