MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, offering environmental sealing and a wide operating temperature range of -65 °C to 200 °C. This harsh environment connector family includes front wall mount, rear wall mount, and jam nut receptacles, along with RFI grounding plugs. With 9 shell sizes and 52 insert arrangements available, they utilize M39029 rear release crimp contacts in various sizes. Constructed with high-strength aluminum shells and offering plating options like cadmium and nickel, these connectors ensure durability and reliability in military and industrial applications.