MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, known for their environmental sealing and wide operating temperature range from -65 °C to 200 °C. This harsh environment connector family offers various receptacle options, including front wall mount, rear wall mount, and jam nut receptacles, with RFI grounding plugs available. With 9 shell sizes and 52 insert arrangements, they utilize M39029 rear release crimp contacts in different sizes, from 22D to 8 (coax and twinax). Constructed with high-strength aluminum shells, these connectors come in multiple plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum. They also include RoHS certified cadmium-free finishes, making them suitable for a range of applications requiring durability and reliability in challenging environments.