MIL-DTL-38999 Series II connectors feature up to 128 contacts housed in a durable insert, designed for harsh environments with an operating temperature range of -65 °C to 200 °C. These connectors, with various mounting options including front and rear wall mount, jam nut, and box mount receptacles, ensure reliable performance in demanding conditions. Available in 9 shell sizes and 52 insert arrangements, they utilize M39029 rear release crimp contacts for secure connections. The aluminum shells come in different plating options like cadmium and nickel, with RoHS compliant finishes. With gold-plated contacts and a bayonet coupling mechanism, these connectors guarantee optimal conductivity and 500 mating cycles, suitable for environment-resistant applications.