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 with RFI grounding plugs, available in 9 shell sizes and 52 insert arrangements. Utilizing M39029 rear release crimp contacts, they accommodate various contact sizes, including coax and twinax. Constructed with high-strength aluminum shells, these connectors come with different plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with RoHS certified cadmium-free finishes. Ideal for military and industrial applications, these connectors ensure reliable performance with their conductive socket contacts and environment-resistant design, suitable for box and through bulkhead mounting receptacle types.