MIL-DTL-38999 Series II connectors feature up to 128 contacts housed in an environmentally sealed insert, designed for extreme operating temperatures ranging from -65 °C to 200 °C. These harsh environment connectors come in various configurations, including front and rear wall mount, jam nut, and box mount receptacles. Available in 9 shell sizes with 52 insert arrangements, they utilize M39029 rear release crimp contacts for reliable connectivity. Constructed with durable aluminum shells, the connectors offer multiple plating options, such as cadmium and nickel, meeting RoHS compliance standards. Ideal for military and aerospace applications, these circular plugs ensure secure and high-performance electrical connections in demanding environments.