The MIL-DTL-38999 Series II connectors, designed for harsh environments, feature up to 128 contacts in an insert with environmental sealing. Operating between -65 °C and 200 °C, they offer various mounting options 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 multiple sizes. Constructed with aluminum shells and offering plating options like gold, electroless nickel, and cadmium finishes, these connectors meet military specifications for reliability. Suitable for applications requiring environmental resistance, they provide secure and conductive connections, with a mating life of 500 cycles. The RoHS compliant versions ensure adherence to environmental regulations.