MIL-DTL-38999 Series II connectors offer up to 128 contacts in an insert, featuring environmental sealing and a wide operating temperature range from -65 °C to 200 °C. These harsh environment connectors include various receptacle styles such as front and rear wall mount, jam nut, and rear/front box mount options. Available in 9 shell sizes and 52 insert arrangements, they utilize M39029 rear release crimp contacts in sizes 22D, 22M, 22, 20, 16, and 12. Constructed with aluminum shells, these connectors come with plating options including light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with RoHS certified cadmium-free finishes. Ideal for military applications, they offer reliable performance with gold-plated contacts, bayonet coupling, and a service rating of M for environment resistance.