MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, offering environmental sealing and an extensive operating temperature range from -65 °C to 200 °C. Designed for harsh environments, they come in various configurations including front wall mount, rear wall mount, and jam nut receptacles with RFI grounding plugs. Comprising 9 shell sizes and 52 insert arrangements, 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 are available in multiple plating finishes such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with RoHS certified cadmium-free options. Ideal for military and industrial applications, these connectors ensure reliable performance with a service rating of I, featuring a bayonet coupling mechanism and removable crimp contacts for easy maintenance.