MIL-DTL-38999 Series II connectors are designed for harsh environments, with up to 128 contacts in an insert and environmental sealing for reliable performance. Operating between -65 °C and 200 °C, these connectors offer durability in extreme conditions. Featuring various mounting options such as front and rear wall mount, jam nut, and box mount receptacles, they cater to diverse installation needs. Available in 9 shell sizes and 52 insert arrangements, they use M39029 rear release crimp contacts for secure connections. Constructed with aluminum shells and offering plating options like cadmium and nickel, they ensure robustness and corrosion resistance. With RoHS compliant finishes, these connectors meet environmental standards while providing a service life of 500 cycles, making them ideal for demanding applications in military, aviation, and industrial settings.