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 configurations including front wall mount, rear wall mount, jam nut, rear box mount, and front 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, they offer plating options like light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum. With RoHS certified cadmium-free finishes, these connectors ensure reliability in demanding applications.