The MIL-DTL-38999 Series II connectors feature up to 128 contacts in an insert, designed for harsh environments with an operating temperature range from -65°C to 200°C. These environmentally sealed connectors come in various configurations including front and rear wall mount, jam nut, and box mount receptacles. Available in 9 shell sizes and 52 insert arrangements, they use M39029 rear release crimp contacts for reliable connections. Made of aluminum with plating options like electroless nickel and cadmium finishes, these connectors meet military specifications for durability and performance in demanding applications. With a keyway polarization, bayonet coupling, and gold-plated contacts, they ensure secure mating and conductivity. Suitable for environment-resistant box and bulkhead mounting, these connectors have a service rating of I and a mating life of 500 cycles, meeting the needs of aerospace, defense, and industrial sectors.