MIL-DTL-38999 Series II connectors are designed for harsh environments, featuring up to 128 contacts in an insert with environmental sealing. Operating between -65 °C and 200 °C, these connectors come in various styles 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 in sizes 22D, 22M, 22, 20, 16, and 12. Constructed with aluminum shells and offering plating options such as electroless nickel and cadmium finishes, they ensure durability. With a bayonet coupling and RoHS certified options, these connectors meet stringent military specifications for reliability in demanding applications.