MIL-DTL-38999 Series I connectors boast up to 128 contacts in a sealed insert, designed for harsh environments with an operating range from -65 °C to 200 °C. Featuring various mounting options such as front wall, rear wall, and jam nut receptacles, along with RFI grounding plugs, they offer versatility in connectivity solutions. Available in 9 shell sizes and 52 insert arrangements, these connectors utilize M39029 rear release crimp contacts for reliable performance. Constructed with high-strength aluminum shells, they come in a range of plating options including cadmium-free finishes for RoHS compliance. Ideal for military and aerospace applications, these circular receptacles ensure secure and durable electrical connections in demanding environments.